FIRST-VOID URINE VERSUS URETHRAL SWAB FOR MOLECULAR DETECTION OF SEXUALLY TRANSMITTED INFECTIONS IN MEN WITH MULTIPLE SEXUAL PARTNERS.

BACKGROUND: Sexually transmitted infections remain a major clinical and global public health burden. Nucleic acid amplification tests are recommended for the molecular detection of urogenital sexually transmitted infections. Although physician-collected urethral swabs have traditionally been used for STI testing in men, swab collection is invasive and may cause substantial discomfort. First-void urine is a promising non-invasive alternative that can support molecular STI testing and screening in men. AIM OF STUDY: To compare first-void urine with physician-collected urethral swab specimens for PCR-based detection of sexually transmitted infections in men with multiple sexual partners. MATERIAL AND METHODS: A prospective paired specimen-comparison study included 148 men aged 22-49 years. Urethral swabs were collected first by a physician, followed by the collection of the initial 20-30 mL of first-void urine. PCR testing targeted Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, and Trichomonas vaginalis. Paired results were analyzed using exact McNemar tests and Cohen's kappa. RESULTS: At least one STI pathogen was detected in 128 of 148 men (86.5%). First-void urine detected at least one pathogen in 128 participants, whereas the urethral swab detected at least one pathogen in 100 participants. All 28 participant-level discordant results were first-void urine-positive/urethral swab-negative (p<0.001). First-void urine yielded higher detection for C. trachomatis (43 vs 38; p=0.063), N. gonorrhoeae (55 vs 45; p=0.002), and M. genitalium (75 vs 62; p=0.0002). T. vaginalis detection was identical in both specimens (27 vs 27). CONCLUSIONS: First-void urine demonstrated equal or higher molecular detection yield than urethral swab for all four STI pathogens studied, supporting its use as a practical specimen for molecular STI testing in men with multiple sexual partners.