Comparison of commercially available enzyme immunoassay with traditional serological tests for detection of antibodies to Coccidioides immitis

Abstract

A newly released commercially available enzyme-linked immunosorbent assay (ELISA) was evaluated for its ability to detect immunoglobulin M (IgM) and IgG antibodies against the tube precipitin and complement fixation (CF) antigens of Coccidioides immitis. The ELISA was compared with more traditional diagnostic assays, CF, latex agglutination (LA), and immunodiffusion (ID). When the IgM-specific portion of the ELISA was compared with LA, there was an agreement of 81.8%, a specificity of 75.0%, and a sensitivity of 84.6%. For the determination of the presence of IgG antibodies, the results of the IgG-specific part of the ELISA were compared with the combined results of ID and CF. After resolution of discrepant results, there was an agreement of 95.6%, a specificity of 98.3%, and a sensitivity of 92.6%. When the results of the IgG- and IgM-specific portions of the ELISA combined were compared with the results of the three traditional assays (CF, LA, and ID) there was an agreement of 96.7%, a specificity of 98.5%, and a sensitivity of 94.8%. The ELISA proved to be a reliable assay for the detection of antibodies against the tube precipitin and CF antigens and did not suffer from the objectivity required to interpret the results of the traditional assays and anticomplement interference associated with the traditional assays.