Improved PCR detection of Chlamydia trachomatis by using an altered method of specimen transport and high-quality endocervical specimens.

Duplicate endocervical swabs were collected for detection of Chlamydia trachomatis by PCR (Roche Diagnostics). One swab was swirled in Specimen Transport Medium (Roche) for PCR testing and discarded. A saline aliquot from the other specimen, sent as a dry swab to the laboratory, was Papanicolaou stained to determine specimen adequacy, and the remainder was PCR tested. Significantly more (24%) PCR-positive results (118 versus 95; P < 0.001) were obtained with the dry specimens than with the swirled specimens when first tested. In addition, PCR-positive results were obtained with 107 (10.6%) of 1,007 microscopically adequate specimens but with only 3 (0.9%) of 341 inadequate specimens (P < 0.001).