Chlamydia trachomatis among sexually active teenage girls: influence of sampling location and clinical signs on the detection rate.

A total of 707 cultures for Chlamydia trachomatis were obtained from healthy teenage girls attending an adolescence clinic for family planning. Apart from sampling from the endocervix, specimens were also obtained from outside the squamocolumnar junction and from the posterior fornix and cultured separately in order to study whether it was possible to improve the detection rate of C trachomatis by sampling from outside the endocervix. In 91 (12.8%) of the girls a positive culture was found. Of the chlamydia positive samples, 83.5% were obtained from the endocervix and 95% from outside the squamocolumnar junction of the portio. Of the 91 positive cultures, 15 (16.5%) were positive only in the sample obtained from the portio surface. The results indicate that the detection rate of C trachomatis could be improved by extended specimen collection. C trachomatis was isolated significantly more often when there was an ectopy, irrespective of whether the specimens had been collected from the endocervix or from outside the squamocolumnar junction. C trachomatis was particularly common if there was an ectopy and a bleeding at specimen collection. If there was no bleeding at sampling, C trachomatis was equally common in women with as in those without an ectopy.