COMPARISON OF SEROLOGIC IMMUNOASSAYS FOR THE DETECTION OF LATEX-SPECIFIC IGE IN SERA

Background: Reported IgE-mediated (type I) reactions to latex have inc reased since the late 1980s. However, characterization of latex hypers ensitivity has been limited by the absence of standardized reagents an d extracts for diagnostic testing. Methods: To assess the performance and diagnostic utility of latex immunoassays, we used clinically defin ed sera from spina bifida patients. We evaluated the Phadezym Modified RAST, CAP System RAST (CAP-1 and CAP-2), and AlaSTAT assay methods an d determined their sensitivity, specificity, predictive values, and ov erall accuracy. The RAST and AlaSTAT assays used a natural latex aller gen; the CAP assay method used a natural (CAP1) and a glove extract al lergen (CAP2). A positive assay result was defined as greater than or equal to 0.35 IU/mL of latex-specific IgE. Results: Of 102 samples tes ted, 34 (33 %) were positive based on clinical criteria. The sensitivi ty of the assays ranged from 88 % (AlaSTAT) to 93 % (CAP1, CAP2); spec ificity ranged from 79 % (CAP1) to 94 % (AlaSTAT). The positive and ne gative predictive values of the assays ranged from 90 % (CAP1) to 97 % (AlaSTAT) and 80 % (AlaSTAT) to 85 % (CAP2), respectively. Overall ac curacy of the assays ranged from 88 % (CAP1) to 90 % (CAP2, AlaSTAT, R AST). Agreement between the CAP1 (natural allergen) and CAP2 (glove al lergen) assays was 98 %. Conclusion: In populations such as persons wi th spina bifida, where the prevalence of latex allergy is high, these immunoassays have good utility for diagnosis of latex allergy.