Prevalence of latex allergy may be vastly overestimated when determined by in vitro assays

BACKGROUND:
The prevalence of latex-specific IgE computed from the results of serologic assays is commonly thought to reflect, to a greater or lesser extent, the prevalence of latex allergy and its implied risk.

OBJECTIVE:
The study examines how imperfect test specificity of in vitro assays influences the precision of latex allergy prevalence that it estimates.

METHODS:
Various models encompassing a range of hypothetical test sensitivity and specificity values are investigated to gauge their influence on the estimate of latex allergy prevalence. The models examine these interactions in situations of high or low allergy prevalence.

RESULTS:
Serologic latex diagnostic assays with test specificity within the range of those of commercially available assays can greatly overestimate prevalence where the true prevalence is low (eg, of the order of one in 100 or one in 1,000). A formula to correct for errors in prevalence estimates arising from imperfect test sensitivity and specificity of an in vitro assay is presented.

CONCLUSION:
While serologic assays for latex IgE pose few hazards to the patient and are useful for confirming the diagnosis of latex allergy, the test results may vastly overestimate the true prevalence of latex allergy and its associated risks in situations where latex allergy is actually rare.