Allergy blood tests(3)

Blood tests for antibodies other than IgE

Studies in the 1970s found that IgG antibodies can also cause allergic reactions in rodents. Therefore, tests for IgG antibodies that bind to food were developed, because IgG antibodies are very abundant (several million-fold more concentrated than IgE) and hence very easy to measure with crude assays such as ELISA. However, IgG antibodies do NOT lead to allergic reactions in human beings. In fact, one of the mechanisms that the body uses to produce immune tolerance is allergen-specific IgG4 antibodies. IgG4 antibodies are immunologically inert, yet they compete with IgE for allergen binding, and since they exist at much higher concentrations, they can effectively block IgE-mediated allergic reactions. Accurate tests that measure allergen-specific IgG4 are useful in determining immunological tolerance, especially during desensitization therapy.

Despite their lack of effectiveness, IgG blood tests are still being heavily promoted for the diagnosis of food allergy and “intolerance”. Many patients have been misled by these tests into believing that they have multiple food allergies, and undergo unnecessary and even harmful food avoidance. More ominously, real food allergy remains undiagnosed, leading to fatal or near-fatal accidents. Any laboratory that promotes food IgG tests for diagnosing allergy is perpetrating healthcare fraud.

 

 

 

 

Reference information: www.allergy.hk/

The information aims to provide educational purpose only. Anyone reading it should consult physician before considering treatment and should not rely on the information above.