[Ligase chain reaction testing of pooled urine specimens to diagnose Chlamydia trachomatis infection].

OBJECTIVE: The purpose of this study was to assess the utility and validity of pooling urine samples for molecular diagnosis of Chlamydia trachomatis infection. MATERIAL AND METHODS: Of 1,220 urine samples collected from Mexican female and male adolescents, 305 pools were composed of fourth individual samples each, based on a calculation of optimal pool size. These were processed by ligase chain reaction (LCR) for the detection of C. trachomatis. Positive and gray-zone pools were reanalyzed individually. Cost savings were calculated comparing actual costs of testing to the cost that would have been incurred testing all 1,220 samples individually. RESULTS: Pools results were: 56 positive, 19 gray-zones and 230 negative. Following individual retesting of positive and gray-zone pools, 59 cases of C. trachomatis infection were identified (4.8% prevalence). Thus, a total of 601 LCR tests were performed, for a 50.4% savings considering only the direct cost of the test. CONCLUSIONS: Our experience shows that sample pooling is both a reliable and convenient tool for CT surveillance in our setting. It should be considered in other similar settings where limited resources constraint surveillance of STIs.