In vitro qualitative ELISA test as a screening tool for significant allergy

The sensitivity and specificity of a new in vitro test (flipSCREEN) for the detection of specific IgE antibody were measured in 40 patients referred for allergy evaluation. Prick skin tests using 1:20 wt/vol antigen were positive if measured wheal diameter was 4 mm or greater. Further testing was done with 1:100 and 1:500 antigen concentration. These skin test results were compared with the graded reaction measured by the qualitative ELISA procedure. Eight pollens and six perennial allergens were tested in each patient. Thirty-four of the 40 patients had two or more positive prick tests; 28 of these patients (82%) had two or more positive qualitative ELISA tests. Sensitivity of the ELISA was 66% for pollens and 52% for perennial antigens. Higher ELISA results were seen with pollens and correlated better with the skin prick test titration results. Specificity was 87% for pollens and 90% for perennial antigens. The qualitative ELISA using appropriate local antigens may be useful in screening patients who would benefit from thorough allergy evaluation.