CHICAGO — Patient-collected rectal swabs are just as accurate as provider-collected swabs for diagnosing chlamydia and gonorrhea infections in men, Dr. Christine Wigen reported at a conference on STD prevention sponsored by the Centers for Disease Control and Prevention
Allowing men to collect their own specimens may help boost testing rates at STD clinics that lack appropriate staff, she said.
“Some STD testing sites don't have [the staff] to take samples from anatomical sites such as the rectum,” she said in an interview. “[They] may only have a phlebotomist to draw blood for HIV or syphilis tests and can only take urine specimens for genitourinary testing of gonorrhea and chlamydia. In the past, the provider had to collect the rectal specimens [so] the test wouldn't be done. With the self-collected method, the testing is possible even in the absence of a provider.”
In addition, she said, if the patient is asymptomatic, then the self-collected method fast-tracks him through the screening process, which would free up the provider to focus on symptomatic individuals and on those with positive tests.
Dr. Wigen examined the accuracy of 225 paired rectal swab samples collected from men who had experienced receptive anal sex in the previous year. Each provided both a self-collected swab and a swab collected by a provider during a visit to the Los Angeles Gay and Lesbian Center sexual health program, a community partner of the Los Angeles County Department of Public Health.
Their mean age was 34 years; 78% said they were gay, 11% said they were bisexual, 8% heterosexual, and 1% transgender.
Overall prevalence of rectal chlamydia was 19%. Provider- and self-collected swabs had a diagnostic agreement of 97%. Rectal chlamydia was found in 39 self-collected specimens and 40 provider-collected specimens. Overall prevalence of rectal gonorrhea was 16%. Provider- and self-collected swabs had a diagnostic agreement of 95%. Gonorrhea was found in 42 self-collected specimens and 37 provider-collected specimens. The sensitivity of self-collected swabs for both infections was 93%. Sensitivity of provider-collected swabs was 95% for chlamydia and 82% for gonorrhea.