Background Specific immunoglobulin E (sIgE) to Ara h 2 is described as a potential factor for diagnosing peanut allergy in children. However for the Dutch children, limited data are available. In this study the diagnostic value of sIgE to Ara h2 for children in a general non-university hospital is evaluated and compared with the existing data.

Methods Data from 137 peanut sensitised children were collected retrospectively. The primary outcome was peanut allergy or tolerance confirmed by food challenges. Different possible predictors, including sIgE to Ara h 2 (n = 52), were identified by multivariate backward stepwise logistic regression analysis. All significant predictors were combined in a formula for prediction of peanut allergy. Different essential cut-off points were obtained by an ROC curve.

Results Multivariate analysis resulted in sIgE to Ara h 2 as only predictor for peanut allergy, with a discriminative ability of 0.87 (95% CI, 0.77–0.97). Sensitivity and specificity values of respectively 55% and 95% were found at a sIgE to Ara h 2 cut-off value of 4.25 kU/L. Hundred percent specificity was reached at a cut-off point of 5.61 kU/L. The mean (SD) sIgE to Ara h 2 level for allergic children was 21.49 kU/L (SD 30.65) compared to 1.07 kU/L (1.56) for tolerant children (p = 0.001).

Conclusions Specific IgE to Ara h 2 is the best predictor for peanut allergy in sensitised children in a non-university hospital, comparable to previously published data. These results are a step forward to a generalisation to the Dutch children population.