Six weeks after total abdominal hysterectomy, a 48-year-old woman reports continuous leakage of urine per vaginam day and night. To differentiate a vesicovaginal fistula from a ureterovaginal fistula at the bedside, which test is performed?

• A Marshall-Marchetti test
• B Ferriman-Gallwey scoring
• C Bonney's test with the bladder neck elevated
• D Three swab test with methylene blue instilled into the bladder ✓

Explanation

In the three swab test, three gauze swabs are placed in the vagina and methylene blue dye is instilled into the bladder. Staining of the top swab blue indicates a vesicovaginal fistula, while a wet but unstained middle swab suggests urine reaching the vagina from above, pointing to a ureterovaginal fistula, which is confirmed by IVU. Bonney's test is used for genuine stress urinary incontinence to distinguish urethral sphincter incompetence from fistula, since stress leakage stops when the bladder neck is elevated, whereas fistulous leakage continues.

Reference: Shaw's Textbook of Gynecology, 17th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.