Chlamydia pneumoniae is a clinically important pathogen, the diagnosis of such infection being based mainly on serology. Microimmunofluorescence (MIF) is the current standard diagnostic method, but is subjective and time-consuming, so the authors tested the serology of chronic cough patients using an EILSA method for the Chlamydial antibody, which is a more objective method, and compared the results with those of the standard method.

Thirty-five patients, who visited Kangwon National University Hospital between August 2003 and July 2004, were evaluated. A MIF and ELISA tests were used to determine C. pneumoniae antibody titers. Nasopharyngeal aspirates were examined by polymerase chain reaction (PCR). The Spearman rank correlation test was used for data analysis.

Sensitivities of ELISA for IgG, IgA and IgM, as judged by MIF, were 84.0, 84.0 and 40.0% and the specificities were 60.0, 60.0 and 96.7%, respectively. Three patients were Chlamydia PCR positive.

ELISA can be a useful tool for studying the seroprevalence of Chlamydia pneumoniae. However, further studies will be required prior to its clinical use.