Two aspects of the performance of Abbott's improved Chlamydiazyme enzyme immunoassay (EIA) were studied. Firstly, the test was compared with cell culture in cervical specimens from 100 abortion applicants. The results showed good correlation between the two methods, with 12 women positive with both methods and one woman EIA-positive but culture-negative. Compared with cell culture the EIA had sensitivity of 100% and specificity of 98.9%. Secondly, the reproducibility of positive EIA tests was evaluated by re-analysing 100 consecutive positive specimens. Ninety-nine of these remained positive and one weakly positive specimen became negative. There was close correlation between absorbance values on first and second analyses. The performance of the Chlamydiazyme EIA in terms of sensitivity, specificity and reproducibility is acceptable in this patient population.