AN ASSESSMENT OF A NEW DIAGNOSTIC INDIRECT ENZYME-IMMUNOASSAY FOR THEDETECTION OF ANTI-MYCOPLASMA PNEUMONIAE IGM

A new and rapid IgM enzyme immunoassay (EIA)(Immuno Well, Gen-Bio, San Diego, CA) was evaluated for its ability to accurately establish a se rodiagnosis for acute Mycoplasma pneumoniae infection. Case definition s were established with the combination of complement fixation (CF) se rology, IgM anti-PI immunoblotting, and clinical and other laboratory data. In an asymptomatic population of 52 children and adults, the EIA was positive for 3.9%. For 17 serum pairs for which there was evidenc e of a greater than or equal to 4-fold rise in CF titer, 5 acute sera (29.4%,) and 14 convalescent sera (82.3%) were positive. In applying t he assay to sera that were acquired from a prospective study of childh ood infection where the positive case definition was maintained for 22 .3% of patients, the sensitivity, specificity, positive predictive val ue, and negative predictive value for the EIA was 90.5%, 93.2%, 79.2%, and 97.1%, respectively. When the EIA results of a ''low-positive,'' as defined by the manufacturer, were excluded from the positive group, the respective values were 81.0%, 97.3%, 89.5%, and 94.7%. The accura cy of this new assay will be influenced by the prevalence of true illn ess in the populations to which it may be applied.