The vaginal introitus: a novel site for Chlamydia trachomatis testing in women

We evaluated the vaginal introitus as a noninvasive sampling site for testing for Chlamydia trachomatis.

Swabs from the vaginal introitus were obtained from 300 women attending a sexually transmitted diseases clinic and tested for the presence of Chlamydia trachomatis by polymerase chain reaction. Additionally, 200 of these women self-collected an additional introitus swab and submitted a urine sample for polymerase chain reaction testing. These samples were compared with polymerase chain reaction, culture, and enzyme immunoassay for Chlamydia trachomatis from endocervical samples and polymerase chain reaction and culture on urethral swabs. Patients were determined to be infected with Chlamydia trachomatis by a positive culture result from any site or a confirmed positive result by polymerase chain reaction with an alternate primer.

The sensitivity of vaginal introitus swabs obtained by health care providers for the detection of urogenital Chlamydia trachomatis was 92% (95% confidence interval 83 to 100), greater than polymerase chain reaction, culture, or enzyme immunoassay of the cervix or urethra. The sensitivity by polymerase chain reaction of patient self-collected swabs was 81%. Sampling of the vaginal introitus, by both health care workers and the patient herself, performed as well as commonly used diagnostic tests that require vaginal speculum examination. The sensitivity of polymerase chain reaction testing of urine samples was 73%.

The vaginal introitus represents a highly effective noninvasive specimen collection site for Chlamydia trachomatis testing by polymerase chain reaction. Self-collection of introitus specimens may revolutionize sexually transmitted disease testing by eliminating the need for a speculum examination by skilled health care personnel.