Serological diagnosis with the Chlamydia Spot-IF test.

Using a set of sera for which full chlamydial micro-immunofluorescence results suggested a clear diagnosis, we have evaluated the Chlamydia Spot-IF test (bioMerieux), which allows a comparison of titres to Chlamydia trachomatis and C. psittaci antigens. A modification of the test in which the antigen slides were pre-treated with a monoclonal antibody to chlamydial lipopolysaccharide, improved its ability to differentiate infections with C. trachomatis from those with C. psittaci or C. pneumoniae.