IMPROVED DETECTION OF CHLAMYDIA-TRACHOMATIS IN ENDOCERVICAL SAMPLES BY USING A NEW POLYMERASE CHAIN-REACTION ASSAY

Aim. To compare the performance of a commercially developed polymerase chain reaction (PCR) assay, Amplicor Chlamydia trachomatis from Roche Molecular Systems, with that of a standard enzyme immunoassay (EIA) s ystem, Chlamydiazyme from Abbott Laboratories, which is currently used throughout New Zealand. Methods. Cervical swabs were collected from 8 19 female patients attending the family planning clinic in Christchurc h. These swabs were then analysed using the Amplicor and Chlamydiazyme assays. Results. The prevalence of chlamydia infection was 4.2% by th e Chlamydiazyme EIA method and 5.3% with the Amplicor PCR assay. In 20 cases, where the results from the two assays were discordant, the con flict was 'resolved' by using a third assay which detects a separate r egion of the chlamydia genome. This gave an overall prevalence of 5.8% of confirmed infections in this group. The Amplicor PCR assay detecte d 29.4% more cases than the usual EIA method. Conclusions. This study demonstrates that Amplicor PCR assay allows improved identification of C trachomatis infections in a population with a relatively low preval ence of infection. The Amplicor PCR assay detects a significant number of additional infections and should be considered for routine use. As the PCR assay is more expensive a shift in the price/payment structur e may be required before this assay comes into widespread use. However , the reduced morbidity resulting from the detection and treatment of otherwise unrecognised cases should also be considered in any cost ben efit analysis.