In reply: Allergen-specific IgE serologic assays define sensitization, not disease (January 2016)

We thank Dr. Hamilton for his interest in our article and for providing more recent literature than was available at the time we submitted our manuscript.

There are multiple points of view toward allergy testing. But the bottom line, as emphasized by Dr. Hamilton and in our article, is that serum IgE testing should not be used as the sole diagnostic tool because it is an indicator of sensitization, not disease, and that clinical history should always be used in conjunction to ensure proper diagnosis.

It is our experience that some clinicians indiscriminately order large panels of serum IgE tests. As Dr. Hamilton indicates, patients can have positive serum IgE results but not display allergy symptoms, which can lead to unnecessary food avoidance. In addition, false-negative results from injudiciously ordered tests (ie, not based on pretest probability) can lead to missed diagnoses. All of these points should be kept in mind in delivering good clinical care, and as such, Choosing Wisely has highlighted the importance of using this test appropriately.

In response to the origin of the sensitivities and specificities used to calculate the sum, the values were curated from available literature and thus limited the number of allergens that could be profiled. A cutoff of 0.35 kU/L was used because this was the cutoff used by the references.

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