The Comparison between Particle Agglutination Assay and Enzyme Immunoassay in the Detection of Mycoplasma pneumoniae-Specific Antibody

ABSTRACT

BACKGROUND: The two common serological test methods used for initial diagnosis of acute Mycoplasma pneumoniae (MP) pneumonia are particle agglutination assay (PA) and enzyme immunoassay (EIA). We compared the differences between the two methods and suggest a test method more suitable for clinical laboratories. METHODS: A total of 35 patients (18 adult and 17 pediatric) performed MP specific antibody test using PA (Serodia-Myco II, Fujirebio, Japan) and EIA (Ani Labsystems, Finland) methods. IgM and IgG antibodies were measured separately by EIA method. PA and both IgM and IgG EIA were tested in 26 patients and PA and IgG-EIA were tested in 9 patients. RESULTS: The concordance rates between PA and EIA were 57.7% for IgM and 65.7% for IgG antibodies. Positive PA results showed better agreement with IgG (77.8%) than IgM (38.9%), while negative PA results showed better agreement with IgM (100%) than IgG EIA results (25%). In adult patients, the correlation between PA titers and IgM (r=0.852, P <0.01) and IgG values (r=0.517, P <0.05) were statistically significant. In pediatric patients, the correlation between PA titers and IgG values (r=0.842, P <0.01) was statistically significant. CONCLUSIONS: In this study, we observed that PA and EIA may not be used alternatively. Therefore, we suggest that use of both PA and IgM-EIA will be the optimal choice for laboratories. However, when laboratories are required to select one from PA or EIA, PA may be more useful to diagnose MP infection.