Chlamydia trachomatis: Molecular testing methods

Screening tests to detect Chlamydia trachomatis infections have advanced to permit the detection of nucleic acids from organisms. The development of these molecular assays that can detect and amplify the specific nucleic acids from the genes of C. trachomatis are called nucleic acid amplification tests (NAATs) and they have expanded the range of available specimen types to include noninvasive samples, as well as the more traditional invasive sample types. These new molecular tests have thereby drastically extended the transit time and conditions from the sample collection to testing in the laboratory. These highly sensitive and specific NAATs are now the primary tests used to screen for C. trachomatis infections. For screening purposes, CDC recommends vaginal swabs from women and urine from men as the sample types. These noninvasive specimen types are most suitable for screening applications since the specimen can be collected in multiple venues, without the requirement of pelvic or urogenital examinations. Vaginal swab specimens are less invasive than endocervical swabs. When women are given the choice, they often prefer them above urine collection. These specimen types have been shown to be equal in sensitivity to endocervical swabs and slightly better than urine specimens for the detection of C. trachomatis. Thus, the use of NAAT assays has the potential to improve screening rates of both symptomatic and asymptomatic individuals for detection of chlamydia infections.