Comparison of results of skin prick tests, enzyme-linked immunosorbent assays and food challenges in children with respiratory allergy.

摘要

The present study was undertaken to investigate if enzyme-linked immunosorbent assays (ELISA) alone or in combination with skin tests could provide a better indicator of clinical food hypersensitivity in children with respiratory allergy. Skin prick tests (SPT) were performed on 64 children with crude antigenic food extracts. Oral food challenges were administered to children to confirm or rule out allergenicity of the food(s) incriminated, on the basis of the clinical history and/or a positive skin test. ELISA tests were then performed on the serum samples of all 64 children of study group as well as 32 children of the control group. SPT was found to be more sensitive as it detected a greater number of food challenge positive patients as compared to ELISA (92.85 vs 28.57 per cent). However, ELISA was found to have better specificity than SPT (88.04 vs 64.30 per cent). Clinically significant in our patients were 18.86 per cent of positive SPT and 4.81 per cent of positive ELISA. Our study shows that an ELISA value within the normal range is a reliable predictor of non-allergy, whereas IgE determination as a screening test for allergy is not reliable. Moreover, ELISA in itself or in combination with SPT had no advantage over SPT alone in correctly diagnosing food hypersensitivity.