Microparticle agglutination versus antibody-capture enzyme immunoassay for diagnosis of community-acquired Mycoplasma pneumoniae pneumonia.

Community-acquired Mycoplasma pneumoniae pneumonia is a common disease which is usually diagnosed by serological methods. The objective of the present study was to understand the diagnostic significance and test characteristics of two different serological tests used to identify current Mycoplasma pneumoniae infection. Three hundred sixty-six patients who suffered from community-acquired pneumonia served as the study population. Six hundred ninety-four (328 paired and 38 unpaired) sera were examined for the presence of antibodies to Mycoplasma pneumoniae with commercial kits based on two serological methods, microparticle agglutination and antibody-capture EIA. Agreement between the two kits was 85.2% when individual sera were compared (kappa = 0.62) and 88.5% when patients were compared (Kappa = 0.69). The positive predictive value and the specificity for the identification of current Mycoplasma pneumoniae infection using a single acute-phase serum were 49.3% and 86.9%, respectively, for the microparticle agglutination method, compared to 91.3% and 97.7% for the antibody-capture EIA method (p < 0.001). The negative predictive value and the sensitivity were 86.3% and 48.1% for the microparticle agglutination, not significantly different from the corresponding values of 86.5% and 61.2% for the antibody-capture EIA. It is concluded that the overall agreement between the two methods tested is good, but not perfect. The methods complement each other in the identification of Mycoplasma pneumoniae as the causative agent in patients with community-acquired pneumonia.