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, Dr. Wigen said.
“Some STD testing sites don't have doctors, physician assistants, or nurse practitioners 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 [and as a result], 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, 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 man provided both a self-collected swab and a swab collected by a clinician 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.
The patients' mean age was 34 years; 78% said they were gay, 11% said they were bisexual, 8% heterosexual, and 1% transgender. They were provided with a collection kit and oral and written instructions on how to collect the sample.
The 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.
The 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%, whereas the sensitivity of provider-collected swabs was 95% for chlamydia and 82% for gonorrhea.