Receiver operating characteristics analyses of food and drug administration-cleared serological assays for natural rubber latex-specific immunoglobulin E antibody

Receiver operating characteristics (ROC) analyses to evaluate and compare t he diagnostic accuracy of Food and Drug Administration (510K)-cleared natur al rubber latex (NRL)-specific immunoglobulin E (IgE) antibody immunoassays have not been performed using well-characterized skin-testing reagents. Se ra were collected from 311 subjects (131 latex puncture skin test [PST] pos itive and 180 PST negative). All masked, coded sera were analyzed for latex -specific IgE antibodies in the Diagnostic Products Corporation microplate AlaSTAT, HYCOR RY-TEC RAST, and Pharmacia-Upjohn CAP System RAST FEIA (CAP) . Diagnostic accuracy was evaluated using GraphRoc for Windows software to construct and analyze ROC curves in relation to the subjects' PST status an d the results of the immunoassays. The ROC areas under the curve (AUCs) +/- standard error based on PST for the, three diagnostic tests were 0.858 +/- 0.024, 0.869 +/- 0.024, and 0.924 +/- 0.017, respectively, for AlaSTAT, CA P, and HY-TEC. The HY-TEC system had a significantly greater AUC based on P ST than those observed for AlaSTAT (P < 0.05) and CAP (P < 0.05) analyses. When the diagnostic tests were probed as to the cutoffs giving maximal diag nostic efficiency compared to PST, CAP and AlaSTAT yielded values of <0.35 kU of allergen IgE (kU(A))/liter,and <0.35 kU/liter while the HY-TEC assay yielded 0.11 kU/liter. The diagnostic efficiencies based on PST in our coho rt at these cutoffs were 87.1, 88.1, and 88.7%, respectively. The HY-TEC as say had a significantly, greater AUC than CAP and AlaSTAT using PST as a di agnostic discriminator in our cohort. When the HY-TEC system was probed at its maximally efficient cutoff (0.11 kU/liter) versus HYCOR's recommended c utoff of 0.05 kU/liter, a loss of sensitivity of 8.4% was observed with a g ain in specificity of 19.5%.