Allergy Testing - Is Profit the Motivation?

I once knew a physician very well who would refer almost every patient with even minimal allergy symptoms for a $ 600 (almost all profit) panel of allergy tests. He would proudly show how this, and the subsequent allergy shots, was increasing his revenue. 

Like many doctors he (I hope) believed the sales pitch and was drawn to the increased profit; rather than paying attention to the actual facts.

We are all aware of allergy symptoms; for example a rash after eating shrimp, or nasal congestion and itchy eyes when exposed to ragweed. And physicians have developed many tests, including blood and skin testing for these allergens.

Unfortunately, the only certain way to detect allergies is to have an actual exposure. IgE blood tests are an expensive way to guess at allergies, and only correlates with real symptoms, whether food or otherwise, about 50% of the time. That means that 1/2 the test results are totally wrong; either you are allergic to something where the blood is negative , or not allergic to something that shows positive. Skin testing have a similar inaccuracy.

So why are these done? In certain cases, IF you show an allergy to something AND the skin or blood test CONFIRMS it then SOMETIMES allergy shots can desensitize you to this. But the testing should be restricted to ONLY those possible allergens you know you could be allergic to, AND only if the patient is willing to get allergy shots! Unfortunately, in many cases the motivation is profit.

The National Institute of Allergy and Infectious Disease has issued recommendations for food allergies based on these facts. To summarize:

• A high proportion of food allergy is caused by relatively few allergens (cow's milk, hen's egg, soy, wheat, peanuts, tree nuts, fish, shellfish).
• Evaluate patients with latex allergy for possible cross-reactivity to banana, avocado, kiwi, chestnut, potato, green pepper, and other fruits and nuts.
• For infants with family history of atopy or eczema , consider partially or extensively hydrolyzed infant formula to prevent rashes.
• Do not routinely recommend that patients with chronic hives avoid foods containing additives.
• Use prick tests and/or serum tests for specific blood testing (IgE) to diagnose food allergy; testing should be focused on suspected foods and test results alone should not be considered diagnostic.
• Do not routinely obtain total IgE levels to diagnose food allergy.
• Unproved tests (allergen-specific IgG measurement, cytotoxicity assays, applied kinesiology, provocation neutralization, hair analysis) should not be used to diagnose food allergy.
• Routine use of patch tests to diagnose food allergy is not recommended.
• Recommend a nutritionist consult for growing children, as elimination diets might affect growth. Be aware of nutritional consequences of elimination diets, including deficiencies of vitamins C and D.

In children with purported food allergies on "elimination" diets, 90% were able to re-introduce these foods without any problems.