Comparison of enzyme-linked immunosorbent assay and radioimmunoprecipitation test for detection of immunoglobulin A antibodies to Mycoplasma pneumoniae in nasal secretions.

An immunoglobulin A (IgA) enzyme-linked immunosorbent assay was developed and compared with the radioimmunoprecipitation test in determinations of IgA antibodies to Mycoplasma pneumoniae. Of 45 nasal secretions obtained from infected volunteers, 42 (93.4%) were positive and 2 (4.4%) were negative in both tests. The IgA enzyme-linked immunosorbent assay is at least as sensitive as the IgA radioimmunoprecipitation test but is simpler and safer and should therefore be preferred.