Clinical Guidelines for Chiropractic Practice in Canada Chapter 5 - Clinical Laboratory Procedures Chapter Outline I. Overview II. Definitions III. List of Subtopics IV. Literature Review V. Assessment Criteria VI. Recommendations (Guidelines) VII. Comments, Summary or Conclusions VIII. References IX. Minority Opinions Chapter Appendices I OVERVIEW Chiropractors are primary health care providers responsible for the assessment of their patients and diagnosis of their presenting complaints, thereby providing the basis for appropriate care. Laboratory diagnosis, for which chiropractors are trained, plays a valuable role. However, present legislation in Canada restricts direct access of chiropractors to clinical laboratories in most provinces. To circumvent this limitation Canadian chiropractors, unlike their colleagues in the United States, must often refer patients to their medical doctors. This process is unsatisfactory both in terms of cost and quality of care. It may be argued that since legislation in various provinces currently prohibits the use of laboratory testing as a diagnostic adjunct for chiropractors, recommendations for specific laboratory tests serve no practical purpose. However, education in laboratory diagnosis is a mandatory component of the curriculum in accredited chiropractic colleges and of licensing board examinations in Canada and the USA. In addition the right to order and/or perform laboratory tests is likely to once more be an integral part of chiropractic practice in Canada in the near future because of changes in technology and the law. In these circumstances the profession should have a set of guidelines in place that clearly defines the parameters within which clinical laboratory testing should be practised. These guidelines also deal with certain laboratory tests which are currently accessible to chiropractors but controversial in nature. This chapter, with minor modifications, has been adopted from the proceedings of the Mercy Centre Consensus Conference (Haldeman et al. 1992). The list of tests which forms the basis for the guidelines does not constitute a comprehensive compilation of all clinical laboratory investigations. Rather it represents tests that are most commonly utilized in chiropractic practice where law permits. Literature for well-established standard procedures is listed in the references, but detailed test descriptions are not possible in the space available. The bulk of this information appears in the Section VI recommendations. It has been divided for the purposes of clinical relevance into four sections: A. General recommendations regarding use of laboratory procedures in chiropractic practice. B. Detailed guidelines for ordering commonly used tests. C. Investigational laboratory procedures. D. Inappropriate laboratory procedures. The Reference Section (Section VIII) is organized by topic to allow the reader to access relevant material upon which this chapter is based. Lastly, this chapter contains an appendix that lists useful examples of clinical laboratory guidelines for the investigation of spinal disorders and common visceral pain disorders. Examples of focused organ/health problem profiles are also presented. II DEFINITIONS For definitions see the Glossary at the end of this publication. Accuracy Case Finding False-Negative Result False-Negative Rate (FNR) False-positive rate False Positive Rate (FPR) False-Positive Result "Gold-Standard' Test Likelihood radio for a positive test result Likelihood ratio Negative ratio for a negative test-result Negative test-result Odds Positive test-result Post-test probability Precision Predictive value negative Predictive value position Pretest probability Prevalence Probability Screening Sensitivity Specificity True-negative rate True-negative result True-positive rate III SUB-TOPICS A. General Recommendations 1. Skill and Training 2. The role of Clinical Laboratory Procedures in Chiropractic Practice 3. Laboratory Selection 4. Office Laboratories 5. Proper Patient Preparation 6. Specimen Collection and Preservation 7. The Need for Laboratory Testing 8. Laboratory Test Selection in Diagnosis 9. Laboratory Test Selection in Screening 10. Laboratory Test Selection in Patient Management 11. Interpretation of Laboratory Reference Values 12. Integration of Clinical Laboratory Data with Other Examination Findings 13. Communication of Laboratory Procedures to the Patient 14. Recording Laboratory Procedures 15. Consultation on Laboratory Procedures 16. Use of Focused Organ/Health Problem-Oriented Test Profiles 17. Use of Investigational Laboratory Tests 18. Novel Application of Established Laboratory Procedures in Chiropractic Practice B. Guidelines for Ordering Commonly Utilized Laboratory Tests 1. Routine Urinalysis 2. Complete Blood Count 3. Erythrocyte Sedimentation Rate 4. Biochemical Profiles 5. Plasma Glucose 6. Serum Urea Nitrogen and Creatinine 7. Serum Calcium 8. Serum Inorganic Phosphorus 9. Serum Total Protein and Albumin 10. Serum Cholesterol 11. Serum Alkaline Phosphatase 12. Serum Prostatic Acid Phosphatase 13. Serum Prostate-Specific Antigen 14. Serum Aspartate Aminotransferase 15. Serum Creatine Kinase 16. Thyroid Function 17. Serum Uric Acid 18. Rheumatoid Factor 19. Anti-Nuclear Antibody 20. HLA-B27 21. C-Reactive Protein 22. Serum Potassium 23. Serum Sodium 24. Serum Iron and Total Iron-Binding Capacity 25. Serum Ferritin 26. Fecal Occult Blood C. Investigational Clinical Laboratory Procedures 1. Analysis of Trace Minerals in Hair 2. Live Cell Analysis 3. Biochemical Biopsy 4. Determination of "Optimal" Reference Values D. Inappropriate Clinical Laboratory Procedures 1. Cytotoxic Testing for Food Allergies 2. Reams Testing and Interpretation of Urine E. Appendix IV LITERATURE REVIEW This chapter has been adopted from the Proceedings of the Mercy Centre Consensus Conference (Haldeman et al. 1992). The literature search utilized the MEDLINE database on CD-ROM from 1980 to February, 1993 for articles using the medical subject heading terms relevant to guidelines for the selection and interpretation of laboratory tests. In addition, the CHIROLARS database was searched for articles related to the use of laboratory diagnosis in chiropractic practice. A manual search of the Chiropractic Research Archives Collection was also accomplished. From these sources bibliographies were compiled which contained both journal articles and textbooks. Materials were selected for inclusion if they contained information on the usefulness of clinical laboratory tests in patient care. Included was information on the principles of test selection and interpretation of procedures commonly used in chiropractic practice. Priority was given to well-designed studies published in peer-reviewed journals. Second priority was given to review articles and textbooks. Role of Laboratory Diagnosis The role of clinical laboratory diagnosis in chiropractic has evolved since the inception of the profession to where currently, laboratory diagnosis courses are taught at all accredited chiropractic colleges. In addition, the majority of jurisdictions in North America allow some form of access to laboratory tests (Lamm, 1989). The chiropractic practitioner, as a portal of entry health care provider, has the responsibility to perform an appropriate clinical examination for the purpose of assessing a patient's current health status and identifying if the patient is a proper subject for chiropractic care. The clinical laboratory can, at times, provide useful information when the findings from the clinical examination are insufficient to answer the questions at hand. The decision to order a test is made on the assumption that the results will appreciably reduce the uncertainty surrounding a given clinical question and significantly change the pre-test probability that a disorder is present. Use of Laboratory Tests Laboratory procedures can be used as screening devices to identify "at risk" patients who may be prone to an illness that can be prevented or diminished by early detection and care. For example, routine measurement of cholesterol can be useful in determining which patients should start on preventive management for atherosclerotic cardiovascular disease. The problem with screening, though, is the number of false-positive results it produces. As the prevalence of a disorder in a population falls, the percentage of false-positive results rises dramatically, so there are five to ten false-positive results for every true-positive one. In order to deal with this situation, many attempts have been made to develop guidelines for selection of appropriate patients and tests for early detection (Eddy, 1991). A second reason for using clinical laboratory tests is to provide assistance in establishing diagnostic hypotheses. The laboratory may be particularly helpful in sorting out whether a patient's clinical complaints are due to a functional or organic disorder. To rule out a disorder, very sensitive tests are most effective in reducing the probability of that disorder. Very specific tests are most effective in raising the probability of the presence of a disorder and thus are useful for ruling in diagnoses. Such tests when abnormal can confirm the presence of a disorder (Sox, 1988). The intelligent selection of an appropriate laboratory test depends on choosing the proper test for the purpose intended. The purpose of the test is affected by the practitioner's estimate of the pretest likelihood that a disorder is present based on an assessment of the available clinical information. The use of a test to exclude or confirm a diagnosis should indicate that the practitioner's best estimate after a careful evaluation of the patient's problem is that the diagnosis in question is either relatively unlikely or probable, respectively. When these principles are followed, the conclusions reached from laboratory test results are likely to be correct and lead to appropriate action (Panzer 1991). Laboratory tests are used for patient management which includes monitoring patient's response to care, the need for care, and determination of prognosis. Compared with tests for screening and diagnosis, tests used for monitoring are more likely to have abnormal results, show a change from previous test values, cause a change in patient care, and be followed up with repeat testing. Determining the optimal frequency for monitoring patients with repeat tests or procedures cannot be based solely on the presence of the disorder but requires the application of principles of normal physiology, knowledge of the tests or procedures used to monitor the disorder, and awareness of factors other than the disorder that may influence the test result. Laboratory Test Characteristics Each laboratory test or procedure possesses a set of characteristics that reflects the information expected in patients with and without the disorder in question. These test characteristics provide clinicians with answers to two fundamental questions: 1) If the disorder is present, what is the likelihood that the test result will be abnormal (positive)? and, 2) if the disorder is not present, what is the likelihood that the result will be normal (negative)? The answer to the first question defines the sensitivity of the test and the answer to the latter defines its specificity. An ideal test is one for which there is no overlap in the range of results among patients with and without the disorder in question. Few tests are ideal. Usually there is an overlap of results among patients with or without a specific disorder. Each point along the distribution of results that overlap defines a set of operating characteristics for the test. As the point used to define an abnormal result (cutoff point) is moved in the direction of patients with the disorder, the sensitivity decreases. As it is moved in the direction of patients without the disorder, the reverse is true. Some tests may be used both to exclude or to confirm a disorder by altering the criteria for a positive test according to the purpose of the test. Knowledge of test characteristics is important in deciding which test to select for a given purpose. The process of confirming a disorder requires a test whose specificity is high. When two or more tests are available for this purpose, the one with the highest specificity is ordinarily preferred. When a test is used either for the purpose of screening or to exclude a diagnostic possibility it must be sensitive. When two or more such tests are available, that with the highest sensitivity is ordinarily preferred. Multiple tests are most helpful when: 1) all are normal, thus tending to exclude the disorder; and 2) when all are abnormal, thus tending to confirm the presence of the disorder. Multiple tests are least helpful when one is positive and the others are normal. If two or more tests are highly sensitive and the primary purpose of the test is to exclude a disorder, the gain in sensitivity obtained by ordering more than one test may be offset by the increase in false-positive results. Reference Ranges for Tests The limits of normal for most analytical tests are determined by measurements done on a large number of subjects and defined as the range encompassed by two standard deviations from the mean value. There are several limitations inherent in this conventional definition. First, the definition excludes approximately 2.5 percent of the subjects whose values lie at the extremes of the distribution curve, rendering them abnormal but presumably not ill. Second, for most measurable biological substances, the distribution curve of test results is skewed rather than symmetric and the method used to express the reference range does not precisely define the central 95 percent of subjects. Third, the reference population used to calculate the limits is not necessarily free of illness. It is assumed that with a large enough sample, the impact of subjects with disease will be diluted. This assumption has been shown to be invalid for many chemistry determinations. The result is often the reporting of reference limits that are too broad. Fourth, few laboratories adjust the reference range for the many factors that may influence the test results other than disease; these include age, sex, weight, diet, time of day, activity, and position of the subject when the specimen is drawn. Last, and most important, the uniform method used to define the reference range does not recognize the many purposes that the test may serve. This range will differ according to whether the clinician is concerned with confirming a condition or excluding one. Although this traditional approach suffers from the above limitations, alternative approaches which create narrower reference ranges should follow acceptable methods in determining those ranges. Laboratory Test Interpretation To ensure proper interpretation of the results of laboratory tests, it is important to consider a prior estimate of the likelihood of the presence of a disorder suspected to be present from the history and clinical examination. This is referred to as a pretest probability or prevalence. When the pretest probability is high, a positive result tends to confirm the presence of a disorder, but an unexpected negative result is not particularly helpful in ruling the condition out. When the pretest probability is low, a normal result tends to exclude the condition, but an unexpectedly positive result is not particularly helpful in confirming the disorder. If the sensitivity, specificity, and prevalence of the condition are known, then one may easily calculate the effect of the test result on the probability of a correct diagnosis. This is referred to as predictive value or post-test probability (Gottfried and Wagar, 1983). Commonly Utilized Laboratory Procedures This chapter contains information on commonly utilized laboratory tests. These tests were selected based upon an informal survey of test utilization by a representative sample of doctors of chiropractic. Each test is described as it relates to its usefulness in screening, diagnosis and patient management. A critical review of the literature on the utility of each test was performed to provide a basis for guideline recommendations. V. ASSESSMENT CRITERIA Rating System 1 assessment criteria are used in this chapter. For an explanation of this system (see p. ...). Suggested Strength of Recommendation Ratings Type A: Strong positive recommendation. Based on Class I evidence or overwhelming Class II evidence when circumstances preclude randomized clinical trials. Type B: Positive recommendation based on Class II evidence. Type C: Positive recommendation based on strong consensus of Class III evidence. Type D: Negative recommendation based on inconclusive or conflicting Class II evidence. Type E: Negative recommendation based on evidence of ineffectiveness or lack of efficacy based on Class I or Class II evidence. VI. RECOMMENDATIONS (GUIDELINES) A. General 5.1 The role of laboratory procedures in chiropractic practice The appropriate use of clinical laboratory procedures in chiropractic practice is for diagnosis, screening, and patient management. Comment: clinical laboratory tests are used by the practitioner to (1) aid in the diagnostic process; (2) to screen for early recognition of preventable health problems; and (3) monitor patient progress and outcomes. It is inappropriate to utilize clinical laboratory procedures for other purposes (e.g., for defensive testing or economic gain). Rating: established Evidence: Class III Consensus level: 1 5.2 The need for laboratory testing Laboratory procedures may be appropriate when the information available from the history, clinical examination, and previous evaluation is considered insufficient to address the clinical questions at hand. Comment: the decision to order, perform or refer for a given test or procedure is made on the assumption that the results will appreciably reduce the uncertainty surrounding a given clinical question and significantly change the pre-test probability that the disorder is present. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.3 Laboratory selection It is recommended that the practitioner who uses the services of a clinical laboratory should be aware of the laboratory's scope of services, recognition (licensure and accreditation), and reputation. Rating: Established Evidence: Class III Consensus level: 1 5.4 Office laboratories The practitioner who performs office laboratory procedures should carry out testing in a manner which meets government (provincial) regulations, and is consistent with quality laboratory practice. Comment: provincial regulations define the scope of testing, qualification of laboratory personnel, and the need and extent of quality assurance and proficiency testing. Rating: Established Evidence: Class III Consensus level: 1 5.5 Proper patient preparation The practitioner should make sure the patient is adequately prepared for laboratory testing, and understands any special instructions he/she must follow to provide an adequate specimen necessary to generate valid laboratory results. Rating: Established Evidence: Class III Consensus level: 1 5.6 Specimen collection and preservation The practitioner should assure that in-office laboratory specimens are appropriately collected and preserved. Rating: Established Evidence: Class III Consensus level: 1 5.7 Laboratory test selection in diagnosis The practitioner should select a laboratory test(s) appropriate for the purpose of ruling out a specific condition(s) or confirming a strong clinical suspicion by considering the sensitivity and specificity of the test(s) and estimating the likelihood of the condition(s) (pre-tested probability) based on his or her assessment of the available clinical information. Rating: Promising Evidence: Class I, II, III Consensus level: 1 5.8 Laboratory test selection in screening The use of laboratory tests for screening purposes should include selection of a highly sensitive laboratory test(s), the appropriate application of the test(s) to health problem(s) which are common, have significant morbidity/ mortality and are preventable and/or amenable to effective care. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.9 Laboratory test selection in patient management (monitoring) The reproducibility (precision) of the test is the most important characteristic when selecting laboratory tests for monitoring. Comment: The optimal frequency for monitoring patients cannot be predicted solely on the basis of knowledge of the disorder or the effectiveness of chiropractic care. It requires the application of normal physiology, knowledge of the natural history of the underlying disorder, tests or procedures used to monitor the disorder and awareness of factors other than the disorder that may influence the test results. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.10 Interpretation of laboratory reference values The practitioner should have an understanding of "normality" as it applies to conventional laboratory reference values in order to appropriately interpret laboratory results. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.11 Integration of clinical laboratory data with other examination ... findings Clinical laboratory data should be integrated with results from other examinations as part of the clinical decision-making process when assessing or monitoring the patient's clinical status. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.12 Communication of laboratory procedures and results to the patient The practitioner should effectively discuss with the patient the purposes, possible complications and clinical significance of the results of laboratory studies conducted or ordered. Rating: Established Evidence: Class III Consensus level: 1 5.13 Recording laboratory results Clinical laboratory results should be recorded in the patient case record. Rating: Established Evidence: Class III Consensus level: 1 5.14 Consultation on laboratory procedures The practitioner should seek assistance when uncertain about appropriate test selection, patient preparation, and/or interpretation of laboratory results. Rating: Established Evidence: Class III Consensus level: 1 5.15 Use of focused organ/health problem oriented test profiles The use of profiles which focus on an organ system and/or health problem in a symptomatic patient can be considered a cost-effective and efficient procedure for generating appropriate laboratory data to help confirm or rule out a diagnosis or clinical impression. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.16 Use of clinical laboratory tests considered investigational Laboratory tests which are considered to be investigational should be used in clinical settings only when part of an acceptable research protocol which is supervised by the staff of a recognized research institution. Comment: research protocols for the evaluation of investigational clinical laboratory tests should take into consideration the actual need for the tests, the inherent properties of the tests, the population characteristics to which the tests are applied, the existence of gold standard tests, the required study population size, and the tests' discrimination abilities relative to sensitivity, specificity and predictive value (Adams, 1990). Research protocols should be approved by an institutional review board. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.17 The novel application of established laboratory procedures in chiropractic practice Novel application of established laboratory procedures should not be used in chiropractic practice as a substitute for conventional application of laboratory procedures in the clinical decision-making process. Comment: novel applications of established tests should be evaluated by appropriate research methods. If used in a patient care setting, informed consent is necessary. Rating: Established Evidence: Class I, II, III Consensus level: 1 B. Guidelines for ordering commonly utilized laboratory procedures 5.18 Guidelines for ordering a urinalysis a. (a) Outpatient screening/case-finding i. A urinalysis is not indicated in asymptomatic individuals whose history and physical examination findings are within the normal ranges for age and sex. ii. In specific subsets of the population with higher prevalence of renal disease, urinary tract infections, liver disease, and diabetes mellitus, the urinalysis may be useful to identify those who are significantly at risk, including but not limited to the following: - pregnancy - elderly (>60 years) men and women - obese individuals with a positive family history of diabetes mellitus - individuals taking hepato - or nephrotoxic drugs - individuals routinely exposed to toxic chemicals in the work or home environment. b. (b) Diagnosis i. The urinalysis is indicated in patients where there are clinical findings suggestive of urinary tract infections, renal disease, diabetes mellitus, and liver disease. The urinalysis should include physical, chemical, and microscopic evaluation. ii. The urinalysis may be useful in patients with previous positive findings for proteinuria, microhematuria, bacteriuria, pyuria, or diabetes mellitus. c. (c) Monitoring I. Repeat urinalysis is not indicated in patients in whom no abnormality is suspected. II. Repeat urinalysis may be useful in the following: - documenting evidence of response to treatment for urinary tract infections, renal disease, and diabetes mellitus - patients in whom there is concern that treatment has not been effective - patients taking medications which are hepato - or nephrotoxic - individuals routinely exposed to toxic chemicals - pregnancy Rating: Established Evidence: Class I, II, III Consensus level: 1 5.19 Guidelines for ordering a complete blood count (CBC) a. (a) Outpatient screening/case-finding i. (i) CBCs are not indicated in asymptomatic individuals whose history and physical examination findings are within reference for age and sex. - Routine use of CBCs in populations of low disease prevalence have a low diagnostic yield ii. In specific subsets of the population with higher prevalence of anaemia, the CBC may be useful to identify those who are significantly anaemic because of poor nutrition or undiagnosed chronic illness, including but not limited to the following: - pregnant women in whom there is a suspicion that iron supplementation or nutrition has not been adequate - the elderly (>75 years old) - recent immigrants from third world countries, especially persons at increased risk of malnourishment - individuals on diets which are nutritionally imbalanced b. Diagnosis of suspected abnormality i. The CBC is useful in the diagnosis of primary haematological disorders and some infections. - The CBC is indicated in patients in whom there are clinical findings suggestive of anaemia, including fatigue, mucous-membrane pallor, sore tongue, peripheral neuropathy, abnormal bleeding, or findings suggestive of polycythemia. ii. The CBC may be useful in conditions that may be associated with anaemia and/or abnormal leucocyte counts, such as rheumatoid arthritis, malignancy (e.g., Lymphoma) and renal insufficiency. iii. The CBC may be useful when fever is present or when infection is suspected, especially when other confirmatory findings are absent. c. Monitoring i. Repeat CBCs are not indicated in patients in whom no abnormality is suspected. ii. Repeat CBCs may be useful in the following: - patients in whom there is concern that treatment has not been effective - documenting evidence of response to treatment for anaemia - patients with infection not improving clinically under collaborative care - patients with leucopenia (leucocyte count is less than 4,500/ul) - patients taking cytotoxic medications Rating: Established Evidence: Class I, II, III Consensus level: 1 5.20 Guidelines for ordering the erythrocyte sedimentation rate (ESR) test a. Outpatient screening/case-finding i. The ESR is not indicated in asymptomatic persons. ii. An ESR should be ordered/performed selectively and interpreted with caution in patients whose symptoms are not adequately explained by a careful history and physical examination. - Significant infections or inflammatory or neoplastic disease are unlikely in such patients, and the ESR must be markedly elevated to be diagnostically useful - extreme elevation of the ESR seldom occurs in patients with no evidence of serious disease. b. Diagnosis i. The ESR is useful for the diagnosis of temporal arteritis (giant cell arteritis) and polymyalgia rheumatica. - A normal ESR virtually excludes the diagnosis of temporal arteritis in most patients who are suspected of having the disease - when there is strong clinical evidence for temporal arteritis and the ESR is normal, further efforts to diagnose temporal arteritis are required. ii. A careful history and physical examination are the most reliable means of making a diagnosis of rheumatoid arthritis. In patients with an equivocal examination, an ESR may be indicated and an abnormal result is supportive of presence of this disease. iii. The ESR may be indicated in the differential diagnosis of solitary bone lesions. iv. The ESR may be indicated in the diagnosis of metastatic breast cancer. v. The ESR may be indicated as a means of excluding suspected vertebral osteomyelitis. vi. The ESR may assist in the diagnosis of certain infectious, inflammatory, and malignant disorders. vii. The ESR may provide assistance in distinguishing spinal pain of organic origin from mechanical origin. c. Monitoring i. The ESR is useful for monitoring temporal arteritis and polymyalgia rheumatica ii. The judicious use of the ESR combined with other clinical and laboratory observations may be of value in patients with rheumatoid arthritis and systemic lupus erythematosus. iii. The ESR may be indicated for monitoring patients with Hodgkin's disease. iv. The ESR may be indicated for monitoring patients with acute rheumatic fever. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.21 Guidelines for ordering biochemical profiles a. Outpatient screening/case-finding i. Biochemical profiles are not routinely indicated for screening asymptomatic patients. ii. Selected components of biochemical profiles may be indicated for screening and/or case-finding in adults: serum glucose, cholesterol and creatinine. iii. Specific components of biochemical profiles that are not indicated for screening include the following: serum calcium, alkaline phosphatase, uric acid, sodium, potassium, chloride, AST, lactic dehydrogenase (LDH), total protein, albumin, and total bilirubin. iv. In cases where current technology and/or cost prohibit selective test ordering, biochemical profiles should be used with caution because of a greater likelihood of false-positive findings in low disease-prevalent populations. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.22 Guidelines for ordering a serum or plasma glucose test a. Outpatient screening/case-finding i. A serum or plasma glucose test is not routinely indicated to screen for diabetes mellitus in asymptomatic, non-pregnant adults. ii. A serum or plasma glucose test may be indicated in individuals who are at increased risk for diabetes mellitus. - Risk factors for diabetes mellitus include age (>50 years), family history in a first degree relative, personal history of gestational diabetes, body weight that exceeds generally accepted standards by at least 25 percent, or membership in an ethnic group that has a high prevalence of diabetes. iii. A serum or plasma glucose test is recommended for all pregnant women to screen for gestational diabetes. - A serum or plasma glucose test obtained after a 50-gram glucose load is the preferred screening procedure. b. Diagnosis i. A fasting or random plasma glucose measurement is useful for the diagnosis of diabetes mellitus in persons who present with symptoms of hyperglycaemia (rapid weight loss, polyuria, polydipsia) and/or diabetes (for example, peripheral neuropathy or peripheral vascular disease). - An oral glucose tolerance test may be indicated to confirm equivocal tests. ii. In patients with clinical findings of hypoglycaemia, a serum or plasma glucose should be ordered. - The true hypoglycaemic syndrome refers to the presence of adrenergic (sweating, tremor, tachycardia, anxiety, and hunger) or neuroglycopenic (dizziness, headache, clouded vision, blunted mental acuity, confusion, abnormal behaviour, coma) signs and symptoms in the presence of a low serum or plasma glucose concentration. c. Monitoring i. A random plasma or serum glucose test is not optimal as the primary modality for monitoring glycaemia in insulin-dependent (type I) diabetic patients. - Frequent self-monitored blood glucose measurement, along with periodic (3-4 times per year) measurement of glycated haemoglobin (glycosylated haemoglobin) are appropriate monitoring evaluations. ii. In non-insulin dependent (type II) diabetes, laboratory performed plasma or serum glucose testing may be indicated every three months. - Self-monitored blood glucose measurement may be indicated one or two times per day to assess glycaemia - glycated haemoglobin measurements are indicated at least two times per year to provide an index of mean glucose levels as a measure of overall chronic glucose control. iii. Laboratory performed fasting and postprandial plasma glucose measurements are indicated in diet-treated gestational diabetes every one to two weeks from time of diagnosis until 30 weeks gestation, and once or twice weekly thereafter. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.23 Guidelines for ordering serum urea nitrogen and creatinine test a. Outpatient screening/case finding i. Serum urea nitrogen and creatinine tests are not indicated in asymptomatic individuals whose history and physical examination findings are within reference ranges. ii. Individuals who have a higher likelihood of developing renal dysfunction may benefit from measuring serum urea nitrogen and creatinine concentrations. - Patients with hypertension, diabetes mellitus, congestive heart failure, cirrhosis, prostatic hypertrophy, exposure to nephrotoxic agents, taking diuretics, eating a high-protein diet, and over 75 years of age, are candidates for these tests. b. Diagnosis i. Serum urea nitrogen and creatinine tests are useful in the diagnosis of renal disorders. - These tests are indicated in patients with clinical findings suggestive of renal dysfunction, such as pallor, anaemia, anorexia, unexplained weight loss, polyuria, urinary hesitancy, nocturia, renal colic, dehydration, retinopathy, hypertension, skin lesions of vasculitis, and/or abnormal urinalysis (high specific gravity, proteinuria, haematuria, pyuria, presence of crystals and/or casts). ii. Measuring serum urea nitrogen and creatinine concentrations, or creatinine alone, may be useful in hypertension or diabetes patients. iii. Conditions in which determination of both the serum urea nitrogen and creatinine concentration may be indicated include but are not limited to the following: - gastrointestinal bleeding, complicated by some degree of renal insufficiency - a suspected diagnosis of water intoxication - syndrome of inappropriate antidiuretic hormone secretion. c. Monitoring i. Measuring serum urea nitrogen and serum creatinine concentration, or creatinine alone, may be useful for the following conditions and at the following frequencies: - uncomplicated hypertensive patients, every one to two years - chronic renal disease, every four to six months - patients in acute renal failure, daily. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.24 Guidelines for ordering a serum calcium test a. Outpatient screening/case finding i. The serum calcium test is not indicated in asymptomatic individuals whose history and physical examination findings are within reference limits for age and sex. ii. The use of serum calcium as a screening test for occult metabolic bone disease or malignancy will result in a low diagnostic yield. - For most of these conditions, the post-test probability of disease after abnormal calcium results is not sufficiently high to warrant the inclusion of calcium determinations in a screening profile. b. Diagnosis i. The serum calcium test is useful in the evaluation of patients who present with clinical evidence of hypercalcemia (anorexia, nausea, constipation, polyuria, polydipsia, bone pain, and mental or neurologic aberrations) or hypocalcemia (paraesthesia, muscle cramps, tetany, weakness, convulsions). ii. The serum calcium test may be useful in the evaluation of patients with hypertension, renal calculi, peptic ulcer disease, metabolic bone disease, malignant disorders, history of previous neck surgery, alcoholism, and acid-base imbalance. c. Monitoring i. Repeat serum calcium measurement is not indicated in patients in whom no abnormality is suspected. ii. Serum calcium may be used to follow the course of hypercalcemia and hypocalcemic disorders and their response to care. - A serum calcium level should be interpreted with knowledge of the serum albumin level Rating: Established Evidence: Class II, III Consensus level: 1 5.25 Guidelines for ordering a serum inorganic phosphorus test a. Outpatient screening/case finding i. The serum inorganic phosphorus test is not indicated in asymptomatic individuals whose history and physical examination findings are within reference limits for age and sex. ii. The use of serum inorganic phosphorus as a screening test for various malignant, inflammatory, bony, renal and metabolic disorders will result in a low diagnostic yield. - For most of these conditions, the post-test probability of disease after abnormal inorganic phosphorus results is not sufficiently high to warrant the inclusion of inorganic phosphorus determinations in a screening profile. b. Diagnosis i. The serum inorganic phosphorus test is useful in the evaluation of patients suspected of having metabolic bone disease, renal disorders, endocrine disorders, and acid-base imbalance. c. Monitoring i. Repeat serum inorganic phosphorus measurement is not indicated in patients in whom no abnormality is suspected. ii. Serum inorganic phosphorus may be used to follow the course of hyperphosphatemic and hypophosphatemic disorders and their response to care. - A serum inorganic phosphorus level should be interpreted with knowledge of the serum urea nitrogen level. Rating: Established Evidence: Class II, III Consensus level: 1 5.26 Guidelines for ordering serum total protein and albumin tests a. Outpatient screening/case finding i. The serum total protein and albumin tests are not indicated in asymptomatic individuals whose history and physical examination findings are within reference limits for age and sex. ii. The use of serum total protein and albumin as screening tests for malnutrition, protein loss or breakdown, and impaired protein synthesis will result in a low diagnostic yield. b. Diagnosis i. The serum total protein and albumin tests may be useful in the evaluation of patients with suspected malnutrition, liver disorders, renal disease, malabsorption, recurrent infections, blood dyscrasias, and malignancies such as multiple myeloma. - Results which fall outside the reference range for these tests may require a protein electrophoresis determination and/or immunoelectrophoresis. c. Monitoring i. Repeat serum total protein and albumin measurements are not indicated in patients in whom no abnormality is suspected. ii. Serum total protein and albumin determinations have limited value in monitoring disorders associated with changes in serum protein levels. Rating: Established Evidence: Class II, III Consensus level: 1 5.27 Guidelines for ordering a serum cholesterol test a. Outpatient screening/case finding i. A total serum cholesterol measurement is recommended at least once in early adulthood and at intervals of five or more years up to age 70. - The LDL and HDL cholesterol and serum triglyceride levels should be measured in persons with an elevated total serum cholesterol. ii. In patients who demonstrate risk factors for coronary artery disease, a serum total cholesterol is indicated to assess cardiac risk. - Risk factors for coronary artery disease include: being male or postmenopausal female, positive family history, smoker, hypertension, history of hyper-cholesterolemia, low HDL-cholesterol levels, diabetes mellitus, previous stroke, peripheral vascular disease, or severe obesity. b. Diagnosis i. The total serum cholesterol is useful in the diagnosis of patients with coronary artery disease and peripheral vascular disease. ii. The total serum cholesterol may be useful in the diagnosis of nephrotic syndrome, pancreatitis, liver disease and hypothyroidism. c. Monitoring i. Total serum cholesterol may be used to follow up hypercholesterolemic related disorders and their response to care. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.28 Guidelines for ordering a serum alkaline phosphatase test a. Outpatient screening/case finding i. The serum alkaline phosphatase test is not indicated in asymptomatic individuals whose history and physical examination findings are within reference limits for age and sex. ii. The use of serum alkaline phosphatase as a screening test for unsuspected skeletal and hepatobiliary diseases provides a low diagnostic yield. - The pretest probability is low in the general population for those disorders most strongly associated with an elevated alkaline phosphatase. - The serum alkaline phosphatase test is not specific for any particular disorder or sensitive enough to identify most patients with a single disease. b. Diagnosis i. The serum alkaline phosphatase may be useful in the evaluation of patients who present with clinical evidence of a skeletal disorder with increased osteoblastic activity, and are suspected of having either Paget's disease of bone (osteitis deformans), osteomalacia, primary bone tumours, metastatic bone tumours or primary hyperparathyroidism. - Clinical evidence may include backache, bone pain, bone swelling, abnormal plain films, bone radiographs, and bone scans. ii. The serum alkaline phosphatase test may be useful in the evaluation of patients who present with clinical evidence of a hepatobiliary disorder such as cholelithiasis with obstruction, drug-induced cholestasis, metastatic tumour or space-occupying lesion in the liver, cirrhosis, hepatitis and alcoholism. - Clinical evidence may include fever, nausea, vomiting, abdominal pain, jaundice, certain medication use, and abnormal liver function tests. iii. The serum alkaline phosphatase test may exhibit abnormal results in a number of other disorders. - These conditions include intestinal disorders, malignancy, malnutrition, congestive heart failure, renal disorders, thyroid dysfunction, diabetes mellitus, and physiological influences (age, pregnancy, non-fasting patient). c. Monitoring i. Repeat serum alkaline phosphatase measurement is not indicated in patients in whom no abnormality is suspected. ii. Periodic determinations of serum alkaline phosphatase may be used to follow the course of a disorder and its response to care. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.29 Guidelines for ordering serum prostatic acid phosphatase test a. Outpatient screening/case finding i. The serum prostatic phosphatase test is not indicated in asymptomatic individuals whose history and physical examination findings are within reference limits for age and sex. ii. The use of serum prostatic acid phosphatase as a screening test for unsuspected cancer of the prostate provides a low diagnostic yield. - Assays for serum prostatic acid phosphatase are not sufficiently sensitive to detect prostatic carcinoma in 70 to 80 percent of patients with localized disease (stage a or b) or 5 to 15 percent of patients with metastatic prostatic disease - specificity is low because nearly every method devised for detecting prostatic acid phosphatase exhibits cross-reactivity with other acid phosphatase isoenzymes found widely in human tissues. b. Diagnosis i. The serum prostatic acid phosphatase test may be useful in the evaluation of patients with clinical evidence of a prostatic carcinoma. - Patients may present with obstructive symptoms (hesitancy, diminished urine stream, dribbling, intermittency), lumbar and/or sacral pain, and have induration or nodular irregularities of the prostate discovered by digital rectal examination. c. Monitoring i. Repeat serum prostatic acid phosphatase measurement is not indicated in patients in whom no abnormality is suspected. ii. Serum prostatic acid phosphatase measurement may be used to monitor cancer patients for recurrence after prostatectomy or other ablative care. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.30 Guidelines for ordering serum prostate-specific antigen (PSA) test a. Outpatient screening/case finding i. The serum PSA test is not indicated in asymptomatic males whose history and physical examination findings are within reference limits for age and sex. ii. The use of serum PSA as a screening test for unsuspected cancer of the prostate provides a low diagnostic yield. - Serum PSA measurements are not sufficiently sensitive to be used alone as a screening test - the specificity of PSA is limited, due to elevations of the antigen occurring in men with benign prostatic hyperplasia or prostatitis. b. Diagnosis i. The serum prostate-specific antigen is a useful test in the evaluation of patients with clinical evidence of prostatic carcinoma. - Serum PSA measurement is a useful addition to rectal examination and ultrasonography in the detection of prostate cancer - PSA is more sensitive but less specific than prostatic acid phosphatase for prostate cancer. c. Monitoring i. Repeat serum PSA measurement is not indicated in patients in whom no abnormality is suspected. ii. Serum PSA measurements may be useful to detect recurrences of prostate cancer. iii. Serum PSA measurements may be useful in monitoring the response to care for prostate cancer. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.31 Guidelines for ordering a serum aspartate aminotransferase (AST) test Note: this test was formerly known as glutamicoxaloacetic transaminase (SGOT). a. Outpatient screening/case finding i. The serum AST is not indicated in asymptomatic individuals whose history and physical examination findings are within reference limits for age and sex. ii. The use of serum AST as a screening test for liver disorders, cardiac disease, and skeletal muscle disorders will result in a low diagnostic yield. b. Diagnosis i. The serum AST test may be useful in the evaluation of patients with suspected liver disorders. c. Monitoring i. Repeat serum AST measurement is not indicated in patients in whom no abnormality is suspected. ii. Serum AST may be used to follow the course of various liver disorders and their response to care. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.32 Guidelines for ordering serum creatine kinase (CK) Note: this test was formerly known as creatine phosphokinase (CPK). a. Outpatient screening/case finding i. The serum CK test is not indicated in asymptomatic individuals whose history and physical examination findings are within reference limits for age and sex. ii. The use of serum CK as a screening test for cardiac, skeletal muscle, and central nervous system disorders will result in a low diagnostic yield. b. Diagnosis i. The serum CK test is useful in the evaluation of patients who present with clinical evidence of acute myocardial infarction. - Fractionation and measurement of CK isoenzymes (CK-MB primarily) augments total CK results. ii. The serum CK test may be useful in the differential diagnosis of chest pain, hypothyroidism and in the detection of skeletal muscle disorders that are not of neurogenic origin, such as Duchenne muscular dystrophy. c. Monitoring i. Measurement of serial levels of serum CK and CK-MB isoenzymes are used to monitor care in acute myocardial infarction. ii. Total serum CK may be used to follow patients with certain primary myopathies. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.33 Guidelines for ordering thyroid function tests a. Outpatient screening/case finding i. Routine testing for thyroid disorders is not indicated in asymptomatic individuals. ii. Case-finding is indicated in women over 50 years of age who have general symptoms that could be associated with thyroid dysfunction. b. Diagnosis i. The sensitive thyrotropin assay (STSH) is useful in the evaluation of patients of either sex who present with clinical evidence of thyroid dysfunction. - If STSH is not available, the free T3, free T4, or free T4 index can be used in the evaluation of suspected hyperthyroidism - for the diagnosis of hypothyroidism, the free T4 or free T4 index, followed by a serum thyrotropin (TSH) test, is acceptable. For patients suspected of having thyroiditis, antithyroid antibody studies may be useful. c. Monitoring i. The STSH test is indicated for monitoring patient response to care. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.34 Guidelines for ordering a serum uric acid test a. Outpatient screening/case finding i. The serum uric acid test is not indicated in asymptomatic individuals whose history and physical examination findings are within reference limits for age and sex. ii. The use of serum uric acid as a screening test for gout will provide a low diagnostic yield. - On the basis of established prevalence, if asymptomatic individuals were screened, those with an elevated uric acid have only a 5 percent chance of having gout. iii. For case finding, with a pretest probability of 10% (prevalence of gout in the U.S. is estimated at 0.3%). The probability that a correct diagnosis will be derived from a positive test is less than 50%. b. Diagnosis i. The serum uric acid test is useful in the evaluation of patients who present with clinical evidence of monoarticular arthritis and are suspected of having gout. - Gout is a disorder of purine metabolism where the presence of an elevated serum uric acid level is one of several criteria necessary for diagnosis. ii. The serum uric acid test may be elevated in a number of disorders other than gout which affect urate production or excretion, or both. - These conditions include: (1) increased nucleic acid turnover related to haematological disorders, malignancy, psoriasis and cytotoxic therapy; (2) reduced excretion due to renal dysfunction, certain drugs and organic acidosis, and (3) miscellaneous causes such as arteriosclerosis and hypertension. ii. Serum uric acid measurement is not useful as a test for renal function because the reference range is wide and the rise in uric acid in renal failure is not constant. c. Monitoring i. Repeat serum uric acid measurement is not indicated in patients in whom no abnormality is suspected. ii. Periodic determinations of serum uric acid may be useful in monitoring patients under care for gout. iii. Serial serum uric acid analyses are sometimes of value in estimating prognosis in toxemia of pregnancy. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.35 Guidelines for ordering a rheumatoid factor test a. Outpatient screening/case finding i. The rheumatoid factor is not indicated in asymptomatic individuals whose history and physical examination findings are within reference limits for age and sex. ii. The use of rheumatoid factor as a screening test for rheumatoid arthritis will result in a low diagnostic yield. - If the rheumatoid factor test is ordered when there is little likelihood of rheumatoid arthritis (e.g., low back pain) and where the pretest probability is low (1 percent), the predictive value will be very low. iii. For case finding, with a pretest probability of 10% (prevalence of rheumatoid arthritis in the U.S. is estimated at 0.5% to 3%), the probability that a correct diagnosis will be derived from a positive test is less than 50%. iv. Many more false-positive results as compared to true positive results will occur from screening. - There is less than a one in five chance in a screening program that an individual with a positive rheumatoid factor test will have rheumatoid arthritis. b. Diagnosis i. The rheumatoid factor test is useful in the evaluation of patients who present with clinical evidence of symmetric polyarthritis and are suspected of having rheumatoid arthritis. - Seronegative patients suspected of having rheumatoid arthritis should be retested in three months. ii. The usefulness of the rheumatoid factor test among patients already known to have rheumatoid arthritis is primarily prognostic. Patients with high titers of rheumatoid factor tend to have more severe disease, subcutaneous nodules, vasculitis, and poorer long-term prognosis. However, individual patients will vary with these manifestations. iii. Rheumatoid factor is positive in a significant subset of patients with other rheumatic and nonrheumatic diseases, but its presence or absence weighs little in the diagnosis of the majority of such diseases. - The disappearance of the rheumatoid factor in a patient with Sjogren's syndrome may herald the onset of lymphoma - the rheumatoid factor is frequently positive in cryoglobulinemia. c. Monitoring i. Repeat rheumatoid factor tests are not indicated in patients in whom rheumatoid arthritis is not suspected. ii. The use of the rheumatoid factor test to guide treatment in patients with rheumatoid arthritis is not recommended. There is little evidence to suggest that a rheumatoid arthritis patient with a highly positive rheumatoid factor test will fare better if treated earlier or more aggressively. iii. The rheumatoid factor test is not a generally accepted measure of improvement in rheumatoid arthritis. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.36 Guidelines for ordering the anti-nuclear antibody test (ANA) a. Outpatient screening/case finding i. The ANA test is not indicated in asymptomatic individuals whose history and physical examination findings are within reference ranges for age and sex. ii. The use of the ANA as a screening test for systemic lupus erythematosus, drug-induced lupus, or mixed connective tissue disease where a moderate pretest probability cannot be estimated will result in a low diagnostic yield. b. Diagnosis i. The ANA test is useful in the evaluation of patients suspected of having systemic lupus erythematosus, drug-induced lupus, or mixed connective tissue disease where a moderate pretest probability is estimated based on the clinical criteria present. ii. A positive test, while nonspecific, increases the post-test probability of disease. - A positive ANA test (titer 1:40) should be followed up with more specific tests such as anti-NDNA and precipitating antibodies (against RNP, SM, RO/SS-A) - however, in a patient over 70 years of age, a titer of 1:40 may be insignificant, and repeat measurement should be obtained to see if the titer increases or is stable. iii. A negative ANA test result is extremely powerful in reducing the probability of these diseases. - In patients who have high probability of systemic lupus erythematosus based on clinical criteria but who have a negative antinuclear antibody assay, a determination for anti-ro or antiphospholipid antibodies may be helpful. c. Monitoring i. Repeat measurements of antinuclear antibodies are not indicated in patients in whom connective tissue disease is not suspected. ii. The ANA test can be used as an aid in the assessment of systemic lupus erythematosus disease activity and as a guide for treatment. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.37 Guidelines for ordering the HLA-B27 test a. Outpatient screening/case finding i. The HLA-B27 test is not indicated in asymptomatic individuals whose history and physical examination findings are within reference limits for age and sex. ii. The use of HLA-B27 as a screening test for ankylosing spondylitis in patients presenting with low back pain will result in a low diagnostic yield. b. Diagnosis i. The HLA-B27 test is not useful for confirmation of the diagnosis of spondyloarthropathies (e.g., ankylosing spondylitis and Reiter's syndrome) when adequate clinical and radiologic criteria are present. ii. However, the HLA-B27 test may be useful in patients with low back pain of insidious onset, minimal tenderness over the sacroiliac joints, normal spinal movement and chest expansion and equivocal radiographic findings where the pretest probability is close to 50 percent for ankylosing spondylitis. - A positive HLA-B27 test increases the likelihood of ankylosing spondylitis significantly and a negative result lowers the likelihood. iii. The HLA-B27 test may be useful in children with spondyloarthropathy, especially those with a history of juvenile chronic polyarthritis, to help establish the diagnosis of ankylosing spondylitis. iv. The HLA-B27 test may be useful in helping to differentiate incomplete Reiter's syndrome from seronegative rheumatoid arthritis and gonococcal arthropathy. c. Monitoring i. The HLA-B27 test is not useful for monitoring spondyloarthropathies including the establishment of prognosis, genetic counselling, and patient management. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.38 Guidelines for ordering the C-reactive protein (CRP) test a. Outpatient screening/case finding i. The CRP test is not indicated in asymptomatic persons. ii. The CRP test should be used selectively and interpreted with caution in patients with symptoms that are not explained by a careful history and physical examination. - Significant infections or inflammatory or neoplastic disease is unlikely in such patients, and the CRP must be markedly elevated or positive to be diagnostically useful. b. Diagnosis i. Measurement of CRP by quantitative methods provides the most clinically useful information. ii. The CRP is useful for the diagnosis of temporal arteritis (giant cell arteritis) and polymyalgia rheumatica. iii. A CRP test may be indicated in patients suspected of rheumatoid arthritis where clinical examination findings are equivocal. vi. Measurement of CRP may be useful in the differential diagnosis of peripheral joint pain. v. The CRP may be indicated in the differential diagnosis of solitary bone lesions. vi. The CRP may be indicated in the diagnosis of metastatic breast cancer. vii. The CRP may be indicated as a means of excluding suspected vertebral osteomyelitis. viii. The CRP may assist in the differential diagnosis of certain infectious, inflammatory, and malignant disorders. ix. The CRP may provide assistance in distinguishing spinal pain of organic from mechanical origin. c. Monitoring i. Measurement of CRP by quantitative methods provides the most clinically useful information. ii. The CRP is indicated for monitoring temporal arteritis and polymyalgia rheumatica. iii. The judicious use of the CRP test combined with other clinical and laboratory observations may be of value in patients with rheumatoid arthritis and systemic lupus erythematosus. iv. The CRP may be indicated for monitoring patients with Hodgkin's disease. v. The CRP may be indicated for monitoring patients with acute rheumatic fever. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.39 Guidelines for ordering a serum potassium test a. Outpatient screening/case finding i. A serum potassium test is not indicated in asymptomatic individuals whose history and physical examination are within reference limits for age and sex. ii. Measurement of serum potassium levels is not useful in general screening of ambulatory care patient populations. b. Diagnosis i. Serum potassium measurement is useful in patients with chronic renal disease, including diabetic renal insufficiency. ii. Serum potassium measurement is useful in patients with hypertension to detect primary hyper-aldosteronism. - Measurements should be made at time of diagnosis and before initiation of care. iii. Serum potassium measurement is useful in patients with symptoms or signs suggestive of renal tubular acidosis. iv. Serum potassium measurement is useful in patients with signs and symptoms suggestive of altered serum potassium concentration, including generalized or proximal weakness, new atrial tachyarrhythmias, nocturia, polyuria, or ileus. c. Monitoring i. Serum potassium measurement is indicated one to two times a year in patients with diabetic renal disease. ii. Serum potassium measurement is indicated in hypertensive patients receiving diuretic therapy. iii. Serum potassium measurement may be useful every three months in diuretic-treated patients concurrently receiving digitalis. iv. Serum potassium measurements may be useful in patients with renal dysfunction, cardiac arrhythmias, diarrhoea, dehydration, Addison's disease and metabolic acidosis in whom there is a change in clinical status. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.40 Guidelines for ordering a serum sodium test A. Outpatient screening i. A serum sodium test is not indicated in asymptomatic individuals whose history and physical examination are within reference limits for age and sex. ii. Measurement of serum sodium levels is not useful in general screening of ambulatory care patient populations. B. Diagnosis i. Serum sodium measurement may be indicated in patients with the following signs or symptoms: - rapid change in weight - rapid change in fluid balance (severe vomiting, diarrhoea, polyuria) - rapid change in mental status - clinical evidence of dehydration or volume depletion. ii. Serum sodium concentration is not indicated in hypertensive patients to identify primary aldosteronism. C. Monitoring i. Serum sodium measurement may be useful as an index of hydration, especially in elderly persons or others who may fail to ingest adequate quantities of water to maintain water balance. ii. Serum sodium measurement may be useful in patients with chronic renal insufficiency at the following frequencies: - at the time of change in clinical status - when serum creatinine reaches 7 to 8 mg/dl; thereafter, every two to three months. iii. Serum sodium measurement may be indicated in most patients at the time of change in clinical status, especially change in mental or neurologic status, fluid balance, weight, or dehydration or volume depletion. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.41 Guidelines for ordering a serum iron and total iron binding capacity (TIBC) tests. A. Outpatient screening/case-finding i. The serum iron and TIBC tests are not indicated in asymptomatic individuals whose history and physical examination are within reference limits for age and sex. ii. In individuals with a moderate to high pretest probability of iron deficiency (e.g., pregnant women, premenopausal females with haemorrhage, premature infants, and the malnourished) a serum iron and TIBC may be useful. iii. Measurement of serum iron and TIBC may be useful in screening for iron overload. B. Diagnosis i. Measurement of serum iron and TIBC are useful in patients whose complete blood count results are consistent with a microcytic hypochromic anaemia. - Calculation of transferrin saturation from the serum iron and TIBC may provide additional diagnostic information. ii. Patients who present with clinical features of iron deficiency may benefit from measurement of serum iron and TIBC tests. iii. Serum iron and TIBC measurements may be useful in the differential diagnosis of microcytic hypochromic anemias. iv. Measurement of serum iron and TIBC may be useful in the confirmation of iron overload. C. Monitoring i. Measurement of serum iron and TIBC have limited value in monitoring the management of patients with iron deficiency anaemia. - A complete blood count (CBC) and an absolute reticulocyte count are useful tests to monitor the management of iron-deficiency anaemia. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.42 Guidelines for ordering a serum ferritin test A. Outpatient screening/case-finding i. The serum ferritin test is not indicated for asymptomatic individuals whose history and physical examination findings are within reference limits for age and sex. ii. In individuals with a moderate to high pretest probability of iron deficiency and with CBC and serum iron/TIBC levels within reference ranges, the serum ferritin test may be useful in detecting the early stages of iron depletion. B. Diagnosis i. Measurement of serum ferritin is useful in anaemic patients who are suspected of having iron depletion but have equivocal serum iron and TIBC results. ii. Serum ferritin measurements may be useful in the differentiation of anaemia of chronic disease from iron deficiency anaemia. - A CRP determination should be performed along with serum ferritin to identify possible effects of chronic disease state on ferritin results. iii. Measurement of serum ferritin may be useful in the detection of iron overload. C. Monitoring i. Serum ferritin measurement may be useful in the determination of the end-point to oral iron therapy. ii. Measurement of serum ferritin may be useful in monitoring iron status of patients with chronic renal disease. iii. Serum ferritin measurement may be useful in monitoring the rate of iron accumulation in iron overload. Rating: Established Evidence: Class I, II, III Consensus level: 1 5.43 Guidelines for ordering a fecal occult blood test A. Outpatient screening/case-finding i. Screening with fecal occult blood test is not indicated for asymptomatic patients under 40 years of age. ii. For persons 40 years and older who have familial polyposis coli, inflammatory bowel disease, or a history of colon cancer in a first-degree relative, screening with fecal occult blood test is recommended annually. - Due to the nature of gastrointestinal bleeding, it is recommended that three consecutive samples be obtained - screening for colorectal cancer with air-contrast barium enema or colonoscopy in addition to annual fecal occult blood test is recommended every 3 to 5 years. iii. Screening with fecal occult blood test is recommended annually for persons 50 years of age and older. - Every 3 to 5 years, in addition to the annual fecal occult blood test, a sigmoidoscopic examination should be performed. B. Diagnosis i. Patients with significant colorectal symptoms (abdominal pain, localized tenderness, diarrhoea or constipation, gastrointestinal bleeding) should have a fecal occult blood test performed as part of a colorectal examination. ii. A fecal occult blood test result should be interpreted with caution. - The influence of diet and nutritional supplements (vitamin c and iron) should be considered as possible causes of false-positive and false-negative results - further evaluation of patients with a positive occult blood test may include an air contrast barium enema plus colonoscopy. Rating: Established Evidence: Class II, III Consensus level: 1 C. Investigational clinical laboratory procedures 5.44 Analysis of trace minerals in hair a. Outpatient screening/case finding i. Hair analysis is not indicated for screening of nutritional status or exposure to environmental toxins in asymptomatic individuals. ii. In specific subsets of the population who are at risk for nutritional imbalances or exposure to toxic substances, the use of hair analysis has not been found to be conclusively informative. b. Diagnosis i. Hair analysis for trace minerals is generally not indicated in the determination of nutritional imbalances or exposure to environmental toxic substances. - Measurement of some elements (e.g., iron or lead) have failed to establish a correlation between hair and tissue levels - hair analysis may be useful for evaluating mercury intoxication of the human body. ii. Hair analysis suffers from many problems with interpretation of results. - Hair mineral content can be affected by shampoo, bleaches, hair dyes and other environmental factors. - The level of certain minerals can be affected by colour, diameter, rate of growth of an individual's hair and the season of the year. - Most commercial hair analysis laboratories have not validated their analytical techniques. - Reference ranges for hair minerals have not been adequately established. - For most elements no correlation has been established between hair levels and other known indicators of nutritional status. iii. Hair analysis may be useful in experimental studies of nutritional status or exposure to toxic substances. - More human and animal studies are needed to validate this technique. c. Monitoring i. Repeat hair analysis for trace minerals is not indicated. ii. The beneficial effects of nutritional therapy based on hair analysis have not been adequately documented. Rating: Investigational Evidence: Class I, II, III Consensus level: 1 5.45 Live cell analysis a. Outpatient screening/case finding i. Live cell analysis is not indicated for screening health problems including nutritional imbalances in asymptomatic patients. b. Diagnosis i. Live cell analysis is not indicated in the determination of organ pathologies, infections, immune status or nutritional status. - Blood indicators which live cell analysis claims are useful in diagnosing health problems have not been validated by adequate scientific studies. ii. Additional studies on the use of dark field microscopy for various diagnoses are needed. c. Monitoring i. Repeat live cell analysis for various health conditions is not indicated. ii. The beneficial effects of patient care based on live cell analysis results have not been adequately documented. Rating: Doubtful Evidence: Class III Consensus level: 1 5.46 Biochemical biopsy: (Multiple Test Analysis Including Protein Electrophoresis and Isoenzyme Fractionation with Predictive Interpretation of Results). Biochemical biopsy utilizes a comprehensive approach to laboratory testing where a multitest biochemical test profile is ordered along with isoenzyme fractionation of common enzymes and a serum protein electrophoresis. It may also include other serum protein analyses and complete blood count. The rationale behind the use of this approach is detection of early pathologies in the subclinical phase. a. Outpatient screening/case finding i. Biochemical biopsy is not indicated for screening health problems in asymptomatic patients. ii. This approach has not met the criteria as an effective screening procedure. The biochemical biopsy may not be sensitive enough to detect early pathology and is indiscriminate as is currently applied to patients with health problems that don't fit the criteria for screening. - This approach increases the probability of test results being outside the reference range and generates a significant number of false-positive results which leads the clinician to follow up on these laboratory abnormalities. iii. Additional research is needed to determine the validity of this approach. b. Diagnosis i. The biochemical biopsy approach to testing is not useful for diagnosis of specific health problems and/or vague multisystem patient complaints. ii. The role of biochemical biopsy as an aid to diagnosis requires further investigation. c. Monitoring i. Repeat determinations of the laboratory tests in the biochemical biopsy is not indicated. ii. The beneficial effects of the biochemical biopsy approach to testing on patient management and health outcomes has not been documented. Rating: Investigational Evidence: Class I, II, III Consensus level: 1 5.47 Determination of "Optimal" Reference Values for Laboratory Tests without Following Acceptable Procedures for the Establishment of Reference Ranges. a. Outpatient screening/case finding i. This approach to interpretation of laboratory reference values is not recommended for screening and/or case findings in asymptomatic patients. b. Diagnosis i. The optimal reference value approach to the interpretation of laboratory values is not useful in the diagnosis of specific health problems and nutritional imbalances because of its unusual way of determining reference ranges and because this approach does not take into consideration biological, analytical and statistical variations. - The reference ranges are determined by measurements performed on a large number of subjects and arbitrarily defined as the range encompassed by two standard deviations. - The distribution curve of test results is skewed rather than symmetric. - The population used to calculate reference ranges is not necessarily healthy. ii. Further research is necessary to determine the validity of this approach to the establishment of laboratory reference ranges. c. Monitoring i. Utilizing the optimal value approach to laboratory interpretation is not useful in monitoring changes in patients' health status. Rating: Investigational Evidence: Class I, II, III Consensus level: 1 D. Inappropriate clinical laboratory procedures 5.48 Cytotoxic testing for food allergies. a. Based on the data derived from controlled investigations, there is poor test reliability. b. This test has not been shown to produce results that can be consistently correlated with other examination findings. c. This test lacks an acceptable scientific rationale, lacks sensitivity and specificity and lacks evidence of clinical effectiveness. Rating: Inappropriate Evidence: Class I, II, III Consensus level: 1 VII. COMMENTS, SUMMARY AND CONCLUSION This chapter attempts to provide a conceptual model for the appropriate use of clinical laboratory tests in chiropractic practice. Although at present there is no Canadian jurisdiction which allows access to the clinical laboratory by chiropractors, these guidelines will stand to emphasize the profession's conviction that the clinical laboratory is often a crucial component of a primary health care provider's armamentarium in the clinical decision making process. However, the true effectiveness of these guidelines will not be known until they are implemented in practice and produce a positive impact on patient care. In the meantime, the recommendations outlined in this chapter must be revised and updated periodically. VIII. REFERENCES The role of Clinical Laboratory Tests in Chiropractic Practice Adams AH. Determining the usefulness of diagnostic procedures and tests. Chiropractic Technique 1990; 2(3):90-93. Gottfried EL, Gerard SK. Selection and interpretation of laboratory tests and diagnostic procedures. In: Samily AH, Douglas RG, Barondess JA (eds). Textbook of Diagnostic medicine. Philadelphia: Lea & Febiger, 1987:19-38. Haldeman S, Chapman-Smith D, Peterson (Jr.) DM (eds). Guidelines for Chiropractic Quality Assurance and Practice Parameters The Mercy Conference ~ Major Recommendations Gaithersburg, Md: Aspen Publishers Inc; 1993. Jaquet P: The importance of laboratory methods in chiropractic diagnosis. Annals of the Swiss Chiropractors Association. 1971; Vol. V. Lamm L. Chiropractic scope of practice. Am J Chiro Med 1989; 2(4):155-159. Vear HJ. Scope of chiropractic practice. In: Vear HJ, ed. Chiropractic standards of practice and quality of care. Gaithersburg: Aspen Publication, 1992:49-67. Wertman BG, et al. Why do physicians order laboratory tests? A study of laboratory test request and use patterns. JAMA 1980; 243:2080-2082. Principles of Appropriate Laboratory Test Selection and Use Baer D, et al. Regulation of physician's office laboratories. Medical Laboratory Observer 1988; Sept:26-32. Black ER, et al. Characteristics of diagnostic tests and principles for their use in quantitative decision making. In: Panzer RJ, Black ER, Griner PF(eds). Diagnostic Strategies for Common Medical Problems. Philadelphia: American College of Physicians, 1991:1-21. Griner PF, et al. Selection and interpretation of diagnostic tests and procedures. Principles and Applications. Ann Intern Med 1981;94:553-600. Kassirer JP. Our stubborn quest for diagnostic certainty. A cause of excessive testing. N Engl J Med 1989; 320(22):1489-1491. Sox HC, Jr. Probability theory in the use of diagnostic tests. In: Sox HC, ed. Common Diagnostic Tests, Use and Interpretation. Philadelphia: American College of Physicians, 1987:1-17. Tetrault G: Sensitivity and specificity of clinical tests. Am J Clin Pathol 1991; 96:556. Woolf SH, Kamerow DB: Testing for uncommon conditions. The heroic search for positive test results. Arch Intern Med 1990; 150:2451-58. Principles of Laboratory Test Interpretation Gottfried EL, Wagar, EA. Laboratory testing: a practical guide. Disease-A-Month 1983; 29(11):1. Panzer RJ, et al. Interpretation of diagnostic tests and strategies for their use in quantative decision making. In: Panzer RJ, Black ER, Griner PF, eds, Diagnostic strategies for common medical problems. Philadelphia: American College of Physicians 1991; 17-28. Skenzel LP. How physicians use laboratory tests. JAMA 1978; 239:1077-1080. Speicher CE, Smith JW. Interpretation of strategies. In: Speicher CE, Smith JW eds. Choosing effective laboratory tests. Philadelphia: WB Saunders Co., 1983:37-46. Statland BE, Winkel P. Selected pre-analytical sources of variation. In: Grasbeck Z, Alstrom T, eds. Reference values in laboratory medicine. The current state of the art. New York: John Wiley and Sons, 1981:127-141. Guidelines for Ordering Commonly Utilized Laboratory Tests Routine Urinalysis Free AH, Free HM. Urinalysis: its proper role in the physician's office. Clinics in Laboratory Medicine 1986; 6(2):253-266. Keil DP, Moskowitz MA. The urinalysis: a critical appraisal. Medical Clinics of North America 1987; 71(4):607-624. Pels RJ, et al. Dipstick urinalysis screening of asymptomatic adults for urinary tract disorders, II. bacteriuria. JAMA 1989; 262(9):1221-1224. Sheets D, Lyman JL. Urinalysis. Emergency Medicine Clinics of North America 1986; 4(2):263-280. Woolhander S, et al. Dipstick urinalysis screening of asymptomatic adults for urinary tract disorders I. hematuria and proteinuria. JAMA 1989; 262(9):1215-1219. Complete Blood Count (CBC) Frye EB, Hubbell FA, Akin BV, Rucker L. Usefulness of routine admission complete blood counts on a general medical service. J Gen Intern Med 1987; 2:373-376. Rich EC, Crowson TW, Connelly DP. Effectiveness of differential leukocyte count in case finding in the ambulatory care setting. JAMA 1983; 249:633-636. Ruttiman S, Clemencon D, DuBach U. Usefulness of complete blood counts as a case-finding tool in medical outpatients. Ann Intern Med 1992; 116:44-50. Shapiro MF, Greenfield S. The complete blood count and leukocyte differential count. An approach to their rational application. Ann Intern Med 1987; 106:65-74. Erythrocyte Sedimentation Rate (ESR) Bedell SE, Bush BT. Erythrocyte sedimentation rate from folklore to facts. Amer J Med 1985; 78:1001-1009. Cunha BA. Interpreting the ESR: an advanced course. Diagnosis 1983; Feb. 62-69. Lewis SM. Erythrocyte sedimentation rate and plasma viscosity. Association of Clinical Pathologists. London: Broadsheet, 1980; 94. Sox HC. The erythrocyte sedimentation rate. Guidelines for rational use. Ann Intern Med 1986; 103:515-523. Biochemical Profiles Cebul RD, Beck JR. Biochemical profiles: application in ambulatory screening and preadmission testing of adults. Ann Intern Med 1987; 106:403-413. Hubbell FA, Frye EB, Akin BV, Rucker L. Routine admission laboratory testing for general medical patients. Med Care 1988; 26:619-630. Sackett DL. The usefulness of laboratory tests in health screening programs. Clin Chem 1973; 19:366-372. Witte DL, Angstadt DS, Schweitzer JK. Chemistry profiles in wellness programs: test selection and participant outcomes. Clin Chem 1988; 34:1447-1450. Plasma Glucose National Diabetes Data Group. Classification and diagnosis of diabetes mellitus and other categories of glucose intolerance. Diabetes 1979; 28:1039-1057. Service FI, O'Brien PC, Rizza RA. Measurements of glucose control. Diabetes Care 1987; 10:225-237. Singer DE, et al. Screening for diabetes mellitus. Ann Intern Med 1988; 109:639-649. Singer DE, et al. Tests of glycemia in diabetes mellitus. Ann Intern Med 1989; 110:125-187. Serum Urea Nitrogen and Creatinine Baum N, Dichoso CC, Carlton CR, Jr. Blood urea nitrogen and serum creatinine; Physiology and interpretations. Urology 1975; 5:583. Beck LH, Kassirer JP. Serum electrolytes, serum osmolality, blood urea nitrogen. In: Sox HC, ed. Common diagnostic tests: use and interpretation. 2nd ed. Philadelphia: American College of Physicians, 1990; 367-389. Checchio MD, Como AJ. Electrolytes, BUN creatinine: Who's at risk? Ann Rev Med 1988; 39:465-490. Serum Calcium Juan D. Hypocalcemia: Differential diagnosis and mechanisms. Arch inter Med 1979; 139:1167-1171. Lafferty FW. Primary hyperparathyroidism: Changing clinical spectrum, prevalence of hypertension, and discriminant analysis of laboratory tets. Arch Intern Med 1981; 141:1761-1766. Mundy G. Calcium homeostasis: Hypercalcemia and Hypocalcemia, 2nd ed. London: Martin Dunitz Ltd, 1990. Wong ET, Freier EF. The differential diagnosis of hypercalcemia: An algorithm for more effective use of laboratory tests. JAMA 1982; 247:75-80. Serum Inorganic Phosphorus Knochel JP. The clinical status of hypophosphatemia: An update. N Engl J Med 1985; 313:47. Yu GC, Lee DB. Clinical disorders of phosphorus metabolism. West J Med 1987; 147:569-576. Serum Total Protein and Albumin Whicher JT, Spencer C. When is serum albumin worth measuring? Ann Clin Biochem 1987; 24:572-580. Whicher JT, et al. The laboratory investigation of paraproteinanemia. Ann Clin Biochem 1987; 24:119-32. Serum Cholesterol Garber AM, Sox HC, Littenberg B. Screening asymptomatic adults for cardiac risk factors: the serum cholesterol level. Ann Intern Med 1989; 110:622-639. Krahn M, et al. Comparison of an aggressive (U.S.) and a less aggressive (Canadian) policy for cholesterol screening and treatment. Ann Intern Med 1991; 115:248-255. Report of the national cholesterol education program expert panel on the detection, evaluation, and treatment of high blood cholesterol in adults. Arch Intern Med 1988; 148:36-39. Schucker B, Bradford RH. Screening for High Blood Cholesterol. Clinics Laboratory Medicine 1989; 9(1):29-36. Serum Prostatic Acid Phosphatase Carson JL, et al. Diagnostic accuracy of four assays of prostatic acid phosphatase. JAMA 1985; 253:665-669. Heller JE. Prostatic acid phosphatase: its current clinical status. J Urol 1987; 137:1091-1093. U.S. preventative services task force. Screening for prostate cancer. In: Guide to Clinical Preventative Services. Baltimore: Williams & Wilkins; 1989:63. Watson RA, Tang DB. The predictive value of prostatic acid phosphatase as a screening test for prostatic cancer. N Engl J Med 1980; 303-387. Serum Prostate-Specific Antigen (PSA) Brawer MK. Laboratory studies for the detection of carcinoma of the prostate. Urologic Clinics N Amer 1990; 17(4):759-768. Catalona WJ, et al. Measurement of prostate specific antigen in serum as a screening test for prostate cancer. N Engl J Med 1991; 324:1156-1161. Chadwick DJ, et al. Pilot study of screening for prostate cancer in general practice. Lancet 1991; 338:613-616. Fiorelli RL, et al. Early detection of Stage A prostate carcinoma: combined use of prostate-specific antigen and transrectal ultra-sonography. JAOA 1991; 91(9):863-870. Labrie F, et al. Serum prostate specific antigen as pre-screening test for prostate cancer. J Urology 1992; 147:846-851. Serum Asparatate AminoTransferase (AST) Chopra G, Griffin PH. Laboratory tests and diagnostic procedures in evaluation of liver disease. Am J Med 1985; 79(8):221-230. Clermont RJ, Chalmers TC. The transaminase tests in liver disease. Medicine 1967; 46:199-207. Kools AM, Bloomer JR. Abnormal liver function tests, how to assess their importance in asymptomatic patients. Postgraduate Medicine 1987; 81(6):45-51. Serum Creatin Kinase (CK) Lee TH, Goldman L. Serum enzyme assays in the diagnosis of acute myocardial infarction. In: Sox HC, ed. Common diagnostic tests, use and interpretation, 2nd ed. Philadelphia: American College of Physicians, 1990; 35-66. Klatt EC, Wasef ES, Wong ET. Creatinine kinase in a biochemical test panel. The high cost of a seemingly inexpensive test. Amer J Clin Path 1982; 77(3): 289-284. Lott JA, Wolf PL. Clinical enzymology, a case-oriented approach. New York: Field, Rich and Associates, Inc, 1986. Thyroid Function Tests DeLos Santos ET, Mazzaferri EL. Thyroid function tests. Guidelines for interpretation in common clinical disorders. Postgraduate Medicine 1989; 85(5):333-352. Feldkamp CS, McKenna MI. Contemporary approach to thyroid disease-emphasizing use of high-sensitivity thyrotropin assays. Henry Ford Hosp Med J 1991; 39(1):25-29. Helfand M, Crapo LM. Screening for thyroid disease. Ann Intern Med 1990; 112(11):840-849. Surks MI, et al. American thyroid association guidelines for use of laboratory tests in thyroid disorders. JAMA 1990; 263(11):1529-1532. Serum Uric Acid Wallace SL, et al. Preliminary criteria for the classification of the acute arthritis of primary gout. Arthritis Rheum 1977; 20:895-900. Rheumatoid Factor Lichtenstein MJ, Pincus T. How useful are combinations of blood tests in "rheumatic panels" in diagnosis of rheumatic diseases? J Gen Intern Med 1988; 3:435-442. Shmerling RH, Delbanco TL. The rheumatoid factor: An analysis of clinical utility. Amer J Med 1991; 91:528-534. Wolfe F, Cathey MA, Roberts FK. The latex test revisited. Rheumatoid factor testing in 8,287 rheumatic disease patients. Arthritis Rheum 1991; 34:951-960. Anti-Nuclear Antibody (ANA) Test Fritzler MJ. Antinuclear antibodies in the investigation of rheumatic diseases. Bull Dis 1985; 35:1-10. Sulcebe G, Morcka K. Diagnostic and prognostic significance of different antinuclear antibodies in more than 1000 consecutive Albanian patients with rheumatic diseases. Clin Exptl Rheumatol 1992; 10(3):255-261. White RH, Robbins DL. Clinical significance and interpretation of antinuclear antibodies. West J Med 1987; 147:210-213. HLA-B27 Baron M, Zendek I. HLA-B27 testing in ankylosing spondylitis: An analysis of the pretesting assumptions. J Rheumatol 1989; 16:631-636. Hawkins BR, et al. Use of the B27 test in the diagnosis of ankylosing spondylitis: A statistical evaluation. Arthritis Rheum 1981; 24(5):743-746. Khan MA, Khan MK. Diagnostic value of HLA-B27 testing in ankylosing spondylitis and Reiter's syndrome. Ann Intern Med 1982; 96:70-76. C-Reactive Protein Kushner I. C-reactive protein and the acute phase response. Adv Int Med 1992; 37:313-336. Kushner I, Volanakis JE, Gewurz H. C-reactive protein and the plasma response to tissue injury. Annals New York Academy Sciences 1982; 389. Marchand A, Van Lente F. How the laboratory can monitor acute inflammation. Diagnostic Medicine 1984; Nov/Dec:57-66. Norris MK. Evaluating C-reactive protein levels. Nursing 1992; 22(5):119. Okamura J, et al. Potential clinical application of C-reactive protein. J Clin Lab Analysis 1990; 4:231-235. Serum Potassium Beck LH, Kassirer J. Serum electrolytes, serum osmolality, blood urea nitrogen, and serum creatinine. In: Sox HC, ed. Common diagnostic tests, use and interpretation, 2nd ed. Philadelphia: American College of Physicians, 1990: 367-389. Martin M, Hamilton R, West MF. Potassium. Emerg Med Clinics N America 1986; 4(1):131-144. Narina RG, et al. Diagnostic strategies in disorders of fluid, electrolyte and acid-base homeostasis. Am J Med. 1982; 72:496-520. Serum Sodium Beck LH, Kassirer J. Serum electrolytes, serum osmolality, blood urea nitrogen, and serum creatinine. In: Sox HC, ed. Common diagnostic tests, use and interpretation, 2nd ed, Philadelphia: American College of Physicians, 1990: 367-389. Janz T. Sodium. Emerg Med Clin N Amer 1986; 4(1): 115-130. Narina RG, et al. Diagnostic strategies in disorders of fluid, electrolyte and acid-base homeostasis. Am J Med 1982; 72:496-520. Serum Iron and Total Iron Binding Capacity Cavill J, Jacobs A, Worwood M. Diagnostic methods for iron status. Ann Clin Biochem 1986; 23:168-171. Fairbanks VF. Laboratory testing for iron status. Hospital Practice 1991; 26 (3 Suppl):168-171. Psaty BM, et al. The value of serum iron studies as a test for iron-deficiency anemia in a country hospital. J Gen Intern Med 1987; 2:160-167. Serum Ferritin Fairbanks VF. Laboratory testing for iron status. Hospital Practice 1991; 26 (Suppl 3):17-24. Patterson C, et al. Iron deficiency anemia in the elderly: The diagnostic process. Can Med Assoc J 1991; 144(4):435-440. Fecal Occult Blood Test Brandeau MI, Eddy D. The workup of the asymptomatic patient with a positive fecal occult blood test. Medical Decision Making 1987; 7(1):32-46. Eddy D. Screening for colorectal cancer. Ann Intern Med 1990; 113:373-384. Knight K, Fielding J, Battista R. Occult blood testing for colorectal cancer. JAMA 1989; 261(4):586-593. Hair Analysis Katz SA, Katz RB. Use of hair analysis for evaluating mercury intoxication of the human body: a review. J Applied Toxicol 1992; 12(2):79-84. Klevay LM, et al. Hair analysis in clinical and experimental medicine. Am J Clin Nutr 1987; 46:233-236. Taylor A. Usefulness of measurement of trace elements in hair. Ann. Clin Biochem 1986; 23:364-378. Live Cell Analysis Lowell JA. Live cell analysis: High-tech hokum. Nutrition Forum 1986; 3(11):81-85. Biochemical Biopsy Fernandes JJ. Realistic expectations of laboratory testing. JAOA 1991; 91(12):1223-1228. Furda A. Biochemical biopsy. East Lansing: Privately published, 1978. Gottfried EL, Wagar ED. Laboratory testing: A practical guide. Disease-A-Month 1983; 29(11):1-41. Black ER, et al. Characteristics of diagnostic tests and principles for their use in quantitative decision making. In: Panzer RJ, Black ER, Grinler PF, eds. Diagnostic strategies for common medical problems. Philadelphia: American College of Physicians 1991:1-16. Optimal Laboratory Values Grasbeck R, Alstrom I. Reference Values in Laboratory Medicine. New York: John Wiley and Sons, 1981. Cytotoxic Testing for Food Allergies Sawyer CE, Adams AH. The cytotoxic leukocyte test. Amer Chiropractic Assoc J 1987; 21(2):59-61. Appendix References Guidelines for Clinical Laboratory Investigation and Laboratory Protocols for Spinal Disorders Deyo R. Early Diagnostic Evaluaton of Low-back Pain. J Gen Intern Med 1986; 1:328-338. Deyo R, Diehl A. Cancer as a cause of back pain: frequency, clinical presentation, diagnostic strategies. J Gen Intern Med 1988; 3:230-238. Waddell G. An approach to backache. Br J Hosp Med 1982; Sept:187-219. Focused Organ/Health Problem Profiles Henry JB, Howanitz PJ. Organ panels and the relationship of the laboratory to the physician. In: Jones RJ, Palulonis RM, eds. Laboratory tests in medical practice. Chicago: Amer Med Assoc, 1980: 25-45. IX. MINORITY OPINIONS None APPENDIX A. Useful Guidelines for Clinical Laboratory Investigation of Spinal Disorders 1. Positive Health History for: Previous malignancy Striking weight loss Persistent pain, more than 50 years old Use of Corticosteroids 2. Positive Clinical Examination for: Systemic signs (i.e., fever) 3. Radiographic findings suggestive of pathology 4. Failure to improve with conservative care (See Chapter 9, Frequency and Duration of Care) B. Laboratory Procedures Which May Be Useful for Spinal Disorders Cause/Dysfunction Tests Mechanical Compression fractureSerum alkaline phosphatase, Total protein, albumin, Serum total calcium. Inorganic P04. Inflammatory Infective: TB of the spineESR or CRP, CBC, Urine and sputum cultures. Other infectious agentsESR or CRP, CBC, Blood culture, Serology. Noninfective rheumatoid arthritisESR or CRP, Joint fluid viscosity, Rheumatoid factor (anti-IgG) Ankylosing spondylitisESR or CRP, CBC, Alkaline Phosphatase, HLA-B27 Metabolic Nutritional OsteoporosisAlkaline phosphatase, Calcium, Inorganic P04, Total Protein, Albumin, BUN, Creatinine, sTSH or FT4. OsteomalaciaCBC, BUN, Creatinine, Calcium, Inorganic P04 Alkaline phosphatase, Total Protein, Albumin, Vitamin D assay. Endocrine: Adrenal Serum electrolytes, Urinary free cortisol Sodium, Potassium. ParathyroidCalcium, Inorganic P04, Ionized calcium, PtH assay, Alkaline phosphatase, Serum chloride (C1/P04 ratio). Other Paget's diseaseAlkaline phosphatase, Calcium, Inorganic P04, Urinary hydroyxproline. Neoplastic Multiple myelomaTotal protein, Albumin, CBC, Serum protein electrophoresis, Urinary protein electrophoresis, Uric acid, BUN, Creatinine, Immunoelectrophoresis, Urinary light chain typing. Metastatic tumoursAlkaline phosphatase, Calcium, Inorganic P04, Uric Acid, Acid phosphatase, Prostate specific antigen (PSA), LDH, Serum protein electrophoresis, ESR or CRP. Primary tumoursSame as metastatic tumours Visceral Referred Pain Myocardial infarctionTotal CK, CK and LD isoenzymes. Primary tumoursSame as metastatic tumours Posterior Peptic ulcerCBC, BUN, Stool, Occult blood test. Acute pancreatitisGlucose, Calcium, Serum and urine amylase, Serum lipase, Serum trypsin. Chronic pancreatitisGlucose, Serum amylase, Serum and serum lipase, Stool fat, Serum bilirubin, Lundh test meal. Chronic pancreatitisGlucose, Serum amylase, Serum and serum lipase, Stool fat, Serum bilirubin, Lundh test meal. Carcinoma of theGlucose, AST, Alkaline pancreas phosphatase, T.bilirubin, GGT, Tumour marker assays, ESR. CholecystitisCBC, T.bilirubin, AST, Alkaline phosphatase, Serum amylase. PyelonephritisUrinalysis, Urine culture, Colony count, BUN and creatinine, CBC, ESR. C. Examples of Focused Organ/Health Problem Profiles Utilization of these procedures requires clinical judgement and appropriateness. Multisystem Involvement with Vague and Unexplained Physical Changes Serum Alkaline Phosphatase Serum LDH Serum Total Bilirubin CBC Serum Urea Nitrogen Serum HDL Serum AST sTSH or Free T4 Index Urinalysis Serum Creatinine Serum Calcium Serum Glucose Serum Inorganic Phosphorus Serum Cholesterol Serum Total Protein Serum Uric Acid Serum Albumin Serum Triglycerides Urinary Tract Involvement Serum Urea Nitrogen Serum Creatinine Serum Uric Acid Routine Urinalysis Urine Culture and Colony Count Hyperlipidaemia and Lipid Transport Disorders Serum Cholesterol Serum Triglycerides Serum HDL Cholesterol Serum LDL Plasma Glucose Serum Uric Acid Thyroid Involvement T4 Free T4 Index T3 sTSH Thyroid Autoantibodies (Anti-thyroglobulin antibody) (Anti-microsomal antibody) Joint and Connective Tissue Involvement ANA ASO-T CRP and/or ESR RA Factor Serum Uric Acid CBC Hepato-Biliary Involvement Serum alkaline Phosphatase Serum Total Bilirubin Serum Cholesterol Serum LDH Serum AST Serum ALT Serum GGT Serum Albumin Serum Protein Electrophoresis Anaemia CBC Reticulocyte Count Serum Iron Serum Iron Binding Capacity (IBC) RBC Folate Direct Coombs (Antiglobulin) Serum B-12 Serum Ferritin Haemoglobin Electrophoresis Pregnancy CBC Blood Group (ABO) Blood Type (RH) Indirect Coombs (antiglobulin) Rubella VDRL (RPR) Hypertension Serum Urea Nitrogen Serum Creatinine Serum Electrolytes Plasma Aldosterone Cardiac Involvement Serum CK Serum LDH (Chest Pain) Metanephrines 24-hour Urine Urinalysis Urinary Free Cortisol Serum CK Isoenzymes Serum LDH Isoenzymes Metabolic Bone Involvement Serum Total Protein Serum Albumin Serum Alkaline Phosphatase Serum Calcium Serum Phosphorus Urinary Hydroxyproline Skeletal Muscle Serum CPK Serum Aldolase Urine Myoglobin Serum Calcium Electrolytes Pancreatic Involvement Serum Amylase Urinary Amylase Serum Lipase Serum Calcium Serum Creatinine Serum Trypsin

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