Besides commercially available serological assays that detect antibodies to major outer membrane protein (MOMP)¹ and lipopolysaccharide (LPS) “in-house” chlamydial heat shock protein 60 (cHSP60) assays are extensively used in assessing serological responses to urogenital Chlamydia trachomatis infection. Although comparison of the different “in-house” assays is difficult owing to a lack of standardisation, there is a consensus among the users of these assays that the anti-cHSP60 responses in women increase with the severity of C trachomatis associated disease, leading to the suggestion that the high amino acid sequence homology between chlamydial and human HSP60 results in autoimmune mediated fallopian tube damage. Owing to the significance of the possible association of the response to cHSP60 and progressive disease, a commercially produced assay that employs defined cHSP60 epitopes should allow for the comparison of results obtained in different laboratories, as well as forward the use of cHSP60 as a diagnostic tool if the assay proves to be relevant in predicting pathology or clinical outcome of a …