Abstract
A new commercial test for chlamydial serology, the MRL-Micro-Immunofluorescent Test (MRL; MRL Diagnostics, USA) was compared with the standard microimmunofluorescence test (MIF) using sera from 246 patients.Chlamydia pneumoniae immunoglobulin G (IgG) antibodies were detected in 46.3% (MIF) and 64.2% (MRL) of sera andChlamydia trachomatis IgG in 23.2% (MIF) and 25.2% (MRL);Chlamydia psittaci IgG antibodies were found with the MRL in 1 % of the sera from a general population and in 17.3% of preselected sera with elevated complement fixation titers. Titers were usually higher with the MRL. IgG titers of ≥ 1∶512 were detected in only 2% of sera using the standard MIF but in 30% using the MRL. In 16 sera from threeChlamydia pneumoniae culturepositive patients, the diagnosis of acute infection could be confirmed serologically in one with the MRL test but in none with the MIF test, indicating a higher sensitivity of the MRL.