Vaginal swabs more reliable than urine for STI testing

Vaginal sampling should be the initial choice offered to patients undergoing testing for chlamydia, gonorrhea, and/or trichomoniasis, according to a systematic review and meta-analysis published in the March/April issue of the Annals of Family Medicine.

Kristal J. Aaron, Dr.P.H., from the University of Alabama at Birmingham, and colleagues conducted a systematic literature review to identify studies between 1995 and 2021 assessing the diagnostic sensitivity of commercially available assays for vaginal swabs versus urine specimens from women.

The researchers identified 28 eligible articles with 30 comparisons for Chlamydia trachomatis, 16 comparisons for Neisseria gonorrhoeae, and nine comparisons for Trichomonas vaginalis. In a pooled analysis, sensitivity for vaginal swabs versus urine was 94.1 and 86.9 percent, respectively, for chlamydia; 96.5 and 90.7 percent, respectively, for gonorrhea; and 98.0 and 95.1 percent, respectively, for trichomoniasis.

"We cannot continue to justify the use of urine except for women for whom collection of a vaginal sample is not acceptable," the authors write. "We strongly encourage clinicians to use the genital sample type for women recommended by the U.S. Centers for Disease Control and Prevention and supported by the evidence in this review for laboratory testing for the sexually transmitted infections Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis."