TABLE 9.

Unvalidated Methods for Diagnosing Food Allergy

Method	Rationale
Muscle testing (or applied kinesiology)	Muscle testing consists of having the patient hold the allergen in his hand with an extended arm. A positive test is found if the arm drops when pressure is applied. The principle is that a “bad” substance will make the muscle weaker. Other versions have the patient chew the food and measure salivation.34
Hair analysis	This test consists in examining the patient’s hair for its mineral content. If a harmful substance has been ingested, it is claimed that it will show in hair composition. This is false. Hair grows slowly (1 cm/month), so even hair closest to the scalp is several weeks old and thus may not reflect current body conditions for purposes of food allergy diagnosis.35
Specific Immuno- globulin G (IgG)	Some companies offer dose-specific immunoglobulin G IgG against a large food panel for a large sum of money. They claim that IgG anti- bodies cause inflammation and that avoiding these foods could cure Crohn’s disease, diabetes, depression, and obesity. Specific IgG against food has not been shown to have any physiological significance. If any, the IgG4 subtype could be a marker of food tolerance, although it has not been validated for clinical use. In addition to the cost, IgG testing may lead to inappropriate diet restrictions.36
Vega testing (electroacupuncture)	This method is a mix of acupuncture and homeopathic medicine. The patient is asked to hold the food in one hand and electric current is measured on a related meridian. Again, this method has no scientific basis and has been shown to be ineffective. In 2001, it was estimated that more than 500 Vega machines were being used in the United States to diagnose allergies.37