Comparison of chemiluminescent immunoassay and ELISA for measles IgG and IgM.

In the context of measles elimination, the identification of recent infections is important for clinical laboratories. Serological diagnosis is achieved by detecting specific IgG and IgM. Recently an automated chemiluminescent immunoassay (CLIA) (Liaison, DiaSorin, Italy) has been used to quantify the measles antibody. The aim of this study was to compare this assay with Enzygnost ELISA (Siemens, Germany), with final classification of discrepancies by indirect immunofluorescence (Euroimmun, Germany). For measles IgM, 204 sera were analyzed: 50 IgM-positive, 104 IgM-negative/IgG-positive, and 50 from other viral infections (B19V, rubella, mumps, CMV, and EBV). For the measles IgG assay, 162 samples were tested: 106 were positive and 56 were negative. For measles IgM, the sensitivity and specificity of CLIA against ELISA were 94% (95% CI: 83.2-98.6) and 100% (95% CI: 97.1-100), respectively; the corrected figures after the final classification of discrepancies were 100% (95% CI: 91.0-100) and 99.4% (95% CI: 96.1-100), respectively. In relation to IgG, the sensitivity and specificity of CLIA against ELISA were, respectively, 97.2% (95% CI: 91.7-99.4) and 92.9% (95% CI: 82.5-97.7), and 95.5% (95% CI: 89.5-98.3) and 100% (95% CI: 91.8-100) after the final classification. CLIA showed excellent sensitivity and specificity in detecting measles IgG and IgM antibodies, eliminating the need to aliquot specimens before carrying out the assay.