COMPARISON OF A PNEUMOCOCCAL COMMON PROTEIN (PSAA) ANTIBODY ELISA ANDA PSAA IMMUNE-COMPLEX ELISA FOR DETECTION OF PNEUMOCOCCAL SERUM ANTIBODY

We examined and compared results from three assays, an enzyme-linked i mmunosorbent assay (ELISA) and two immune complex ELISAs for analysis of the serum antibody response to a native pneumococcal 37-kD common c ell-wall protein by using acute-and convalescent-phase sera from 56 pa tients with community-acquired pneumonia. The sensitivities of the ELI SA, the undissociated and dissociated immune complex assays were 85% ( 23 of 27), 78% (21 of 27) and 67% (18 of 27), respectively. To determi ne specificity, paired sera from patients with pneumonia of other bact erial etiologies were tested. The specificities were 83, 83 and 72% fo r the ELISA, undissociated immune complex, and dissociated immune comp lex, respectively. Based on this study, the sensitivities of the three assays were not statistically different. These tests could be used re trospectively to confirm invasive pneumococcal disease.