Enzyme-linked immunosorbent assay compared with indirect immunofluorescence test for detection of Pneumocystis carinii specific immunoglobulins G, M, and A.

An ELISA to measure Pneumocystis carinii-specific IgG, IgM, and IgA has been developed. The antigen was prepared from purified cysts by sonication and ultracentrifugation. Antigen particles with sedimentation coefficients less than 165 S were used. The technique has been compared with indirect immunofluorescence, using whole cysts as antigen. Ninety human sera were assayed. The results were significantly correlated. The ELISA-technique was more sensitive, and owing to the soluble antigen the daily variation was less than 1 per cent. The technique is useful for quick and reliable detection of Pneumocystis carinii antibodies in a routine laboratory.