Diagnostic utility of PCR-enzyme immunoassay, culture, and serology for detection of Chlamydia pneumoniae in symptomatic and asymptomatic patients

This is the authors' abstract. We don't add key points for this paper.

To assess the utility of PCR-enzyme immunoassay (EIA) for diagnosis of acute infection with Chlamydia pneumoniae, we compared tissue culture, PCR-EIA, direct fluorescent-antibody (DFA) stain, and serology in studies with 56 patients with respiratory symptoms and 80 asymptomatic persons. Thirty-five patients were positive by either culture or PCR-EIA, and 101 were negative by both assays. Thirty specimens from symptomatic patients and one from an asymptomatic patient were culture positive; 23 of these were also PCR-EIA positive. Of the eight culture-positive, PCR-EIA-negative specimens, five were DFA negative and three were DFA positive. Four additional specimens were culture negative and PCR-EIA positive; of these, three were DFA positive and one was DFA negative. When we used culture- and/or DFA-positive results as a reference or "gold standard," the sensitivity and specificity of PCR were 76.5 and 99.0%, respectively. When we used PCR- and/or DFA-positive results as the reference, the sensitivity of culture was 87.5%. On the basis of single acute serum specimens, only 8 of these 35 patients had diagnostic antibody titers. Of the asymptomatic patients, 75% had immunoglobulin G or immunoglobulin M antibody to C. pneumoniae; 15 (18.8%) of these had antibody levels considered to be diagnostic of acute infection. This multicenter study indicates that culture and/or PCR-EIA is more reliable for prompt diagnosis of C. pneumoniae infection than single-point serology alone.