Regarding Total IgE level in relationship to Allergen Specific IgE values
In some patients with positive allergen specific IgE test results, non-elevated levels of total IgE are found. This may lead to questions regarding the validity of the positive result of an allergen specific IgE. It is well known that as measured, serum specific IgE can be elevated while total serum IgE may be within the normal range for a clinically allergic individual. This holds true for children as well as for adults.
Measured values of Total IgE in the serum of an allergic individual are known to exhibit only a modest correlation with allergic sensitization. Generally, the mean total IgE in an allergic population is higher than that found in non-allergic individuals. However, there is significant overlap between these two groups. In arguably the most widely referenced textbook of clinical allergy, Middleton’s Allergy: Principle and Practice, the authors refer to this lack of diagnostic utility of total IgE in differentiating atopic individuals defined as demonstrating allergen specific allergic sensitivities from non-allergic persons and provide this summary statement: “Many studies have shown that total serum IgE concentrations tend to be higher in adults and children with allergic diseases compared with nonallergic individuals, but despite these suggestive relationships, the diagnostic value of total serum IgE concentrations is limited.” (Middleton's Allergy: Principles and Practice, Eighth Edition, p1110, Copyright 2014 by Saunders)
The allergen specific test results from the Hitachi Diagnostic test kits for determining allergen specific sensitivities can be trusted even in the setting of an atopic individual failing to demonstrate an elevated Total IgE level.
Vivian Saper, MD, FAAAAI
Medical Director