The Traditional Chinese Medicine (TCM) analysis for the the meridian system is based on pulse diagnosis. This
involves taking pulse readings, twice on each wrist; the first three
lightly, and the next three deeply (for a total of 12 readings).
Each pulse reading must be analyzed for 28 separate pulse characteristics!
The Asian masters, who palpate the 12 pulse positions, may take as
long as 15-20 minutes per wrist. Thus, they can only treat 6
to 8 patients a day by the “traditional method”.
All this changed in the early 1950s, with the development of Ryodoraku
by Dr. Yoshio Nakatani of Japan. Nakatani developed his
procedure of electronic evaluation by measuring skin conductance at
the yuan (source) points of the wrist and ankle. He created one of the
most significant acupuncture diagnostic methods yet created in
either contemporary or traditional acupuncture. When one
compares the findings of Asian masters of pulse diagnosis with the findings of ryodoraku, they are most often identical or extremely close. 
With ryodoraku, you take 12 measurements on each side of the body.
Then, one plots the “readings” on a graph, as below:
To make a graph, one would take and plot all 24 measurements, which will range from zero to 200. Then, you divide that sum by 24, to get the “average”, or “median” reading. The accepted “standard deviation” is 15. In this graph, the
average is 75, with a range from 60-90. Notice how many of the meridians are out of balance in this individual! Readings
outside the “range” are out of balance. If a meridian is too
full of energy, it needs to be sedated. If it is deficient in energy, it needs to be tonified.
The greatest achievement of ryodoraku over pulse diagnosis was realizing that there could be a third balance issue. Traditionally, meridians are evaluated by comparing them with each other. The diagnosis was that a particular meridian had “too much” or “not enough” Qi energy, as compared to the other meridians. BUT, there are 12 meridian pathways on each side of the body! With ryodoraku, it became apparent that a particular meridian could be out of balance with itself, that is, from one side of the body to the other!
The early rydoraku procedure was time consuming, but very accurate.
Fortunately, my acupuncture master,
John Amaro, DC helped to design a software program called EMI (Electro
Meridian Imaging) which does all the mathematical calculations and graph
preparation instantly! Your doctor takes readings with the
ryodoraku unit (see it below) and enters the values in the EMI program.
The program generates a graph of the readings, and demonstrates
the tonification, sedation, and the “luo” points, which can balance the meridians which may be out of balance.