Diagnostic accuracy of specific IgE to components in diagnosing peanut allergy: a systematic review

The diagnostic accuracy of skin prick test (SPT) and specific IgE (sIgE) to peanut extract in diagnosing peanut allergy is suboptimal. Recent studies have evaluated sIgE to peanut components as a possible new diagnostic tool. The aim of our review was to systematically search the literature to assess the diagnostic value of sIgE to peanut components in diagnosing peanut allergy. A literature search was performed in PubMed, Embase and the Cochrane Library. Results were subsequently screened for in- and exclusion criteria. The quality of eligible studies was assessed using a standardized quality assessment tool (QUADAS-2). Data on sensitivity, specificity, and positive and negative likelihood ratios were extracted or calculated for a descriptive analysis. Twenty-two studies were eligible, of which 21 studies in paediatric populations. Most studies reported on sIgE to peanut extract (15) and sIgE to Ara h 2 (12), followed by SPT (9) and sIgE to Ara h 1 (7). All studies were at risk of bias or caused applicability concerns on at least one item of the quality assessment tool. The best combination of diagnostic accuracy measures of all diagnostic tests was found for sIgE to Ara h 2. This finding was independent of geographical location. Compared to SPT and sIgE to peanut extract, sIgE to Ara h 2 was mainly superior in diagnosing peanut allergy in case of a positive test result. Worst diagnostic accuracy measures were found in general for sIgE to Ara h 8 and sIgE to Ara h 9. sIgE to Ara h 2 showed the best diagnostic accuracy of all diagnostic tests to diagnose peanut allergy. Compared to the currently used SPT and sIgE to peanut extract, sIgE to Ara h 2 was superior in diagnosing peanut allergy and should therefore replace these tests in daily clinical practice, especially in children.