Title: Food Allergy Tests
Key words: Food intolerance, Type I allergy, IgE, Type II allergy, IgG, RAST, FAST, ELIZA, intradermal tests, cytotoxic tests, electrodermal tests, kinesiology, radionics, auriculo-cardiac reflex
Date: May 1999
Category: 14. Measurement
Author: Dr van Rhijn
Numerous external factors cloud the controversial food allergy tests by incorrectly labelling food intolerance (non-immunological) as an allergy (immunologically mediated). The classical, rapid Type I allergic reaction, which is IgE mediated and tested conventionally with the Patch and Skin prick test 1, Radioallergoabsorbent (RAST) Test, Type III, IgG mediated tests (FAST & ELIZA) are unreliable due to false negative and positive reactions2, hence the rise of numerous "alternative" methods that will be discussed below.
Progressively highly diluted extracts (allergens) are injected intradermally and used for detecting delayed-onset food reactions 3 similar to the patch test 4, as well as providing a treatment for neutralisation. It is safe, without any recorded cases of anaphylaxis, however, uncomfortable, time-consuming and unreliable, as neutralisation is equally effective with saline 5.
The expensive leucocytotoxic tests (Bryans) measures morphological changes in neutrophyls (Neutron) and lymphocytes (ALCAT) 6 following exposure to food products. Results do not correlate with patients complaints 7 severity, but show 65% reliability 8, good reproducibility 9 and comparability 10. The Food Allergen Cellular Test (FACT), measures a chemical mediator, leucotrine (by ELISA system) release from white blood cells following exposure to 154 food allergens, and is only 80% accurate.
Blinded duplicate hair samples of subjects with established fish allergies (skin prick test), sent to 5 commercial labs tested negative for both samples negative11 and thus unreliable.
Operator Dependent Tests
Electrodermal (VEGA) Test
This technique (Schimmel12 & Voll) measures bioelectrical potentials via a galvanometer and skin electrical resistance via a probe on specific acupuncture points in response to allergens placed into a metallic honeycomb. A drop in resistance may indicate an allergy13 or intolerance to the tested product and claim 96 % accuracy14. Approximately 90 % of patients reported symptom improvement upon detected allergen elimination, with recurrence upon re-exposure. It is cheap, safe, non-invasive and numerous products can be tested in a short time yet its usefulness is not supported by proper controlled trials15.
Muscle tone and strength is tested by a holding bottled food samples in the patient's energy field. The test is inconsistent and concordant rates for blind samples equals the rate expected by chance16.
Food intolerance is detected with the use of a pendulum, with or without the presence of the patient or even the food sample. This technique is obviously extremely subjective.
Confirmation of allergy when detecting a rise in pulse rate following applications of foods in filter papers on the skin of the forearm and shining a light on the ear lobe. It is slow and laborious and lack scientific validation studies.
Alternative methods, especially the operator dependent tests are currently not recommended due to their unreliability and generally inaccuracy in detecting food allergies. Dietary elimination and food challenge17 with an oral provocation test is still the gold standard. This is probably the only reliable way to detect food allergy or intolerance18, 19, but may take six to eight weeks to assess.