Electrodermal Testing1 is a quick, safe and painless method of checking an individual's response to a variety of substances that may be triggering an adverse reaction. The results of this test are considered in conjunction with the patient's medical history and if indicated, further tests can be requested.

In common with other forms of intolerance testing, the validity of this method of identifying sensitivities to allergens has yet to be fully established by the medical and scientific professions. Consequently, it cannot be considered diagnostic on it's own. However, the results of one study using this method in diagnosing inhalant allergies found it to be 96% accurate.[2]

The Electrodermal Test utilises an apparatus called a Wheatstone Bridge, which measures electrical resistance by passing a small electric current between two points of the body. The nervous system conducts electricity but becomes more resistant when presented with a substance that the body recognises as a potential threat. This is the basis for identifying substances that may cause an inappropriate reaction when they come into contact with the immune system.

The apparatus must be specifically calibrated for each individual. Whilst the patient holds one electrode in their hand, the doctor will carry out the necessary calibration using a second electrode to complete the circuit, usually on the patient's foot. The normal level of current flowing through the body is then measured on a galvanometer. Each substance to be tested is placed into the circuit in turn and a reading of the resulting electrical flow is taken. Each item takes around 15 seconds to assess. Foods, additives and medications that do not affect the normal reading are passed as non-problematic. Any substances that impede the ability of the nervous system to conduct the current normally, giving a low reading, are identified as possible allergens.

It is essential that the person conducting the test be well trained and experienced in this method. Electrodermal Testing is a very reliable indicator of intolerances when accurately administered and supported by diagnostic skill.

Depending on the conclusions drawn, an appropriate diet or treatment is prescribed to which most patients respond positively. A diagnosis can only be made once elimination has brought about improvement and challenging causes symptoms to return.

References:

1. NOMA (Complex Homeopathy). Basic Vega Testing Protocol Course. Southampton, pp1-82, 1995.
2. Krop J, FaaemGT, Lewith GT, et al. A double-blind, randomised control investigation of Electrodermal Testing in the diagnosis of allergies. J Alternative and Complementary Medicine. Vol 3, No 3, 1997, pp 241-248.