THREE SWAB TEST- Dye found in the top swab in a three swab test is indicative of?

Dye found in the top swab in a three swab test is indicative of?
A. Uretero-vaginal fistula
B. Vesico-vaginal fistula
C. Urethro-vaginal fistula
D. Rectovaginal fistula

Correct answer : A. Ureterovaginal fistula

Common locations of obstetric fistula

THREE SWAB TEST

• Three swab test is used to differentiate between ureterovaginal fistula, vesicovaginal fistula and urethrovaginal fistula.
• Three cotton swabs are placed in the vagina – at the vault, in the middle and just above the introitus.
• Methylene blue is introduced into the bladder using a rubber catheter.
• The patient is then asked to walk about for 5 minutes.
• The swabs are then retrieved for inspection.

Interpretation of three swab test

• Top swab soaked in urine, unstained – Uretero-vaginal fistula
• Middle swab stained with dye – Vesico-vaginal fistula
• Bottom swab stained with dye – Urethro-vaginal fistula

AIIMS PG ENTRANCE MAY 2015 – MCQ 33

Image credits: Author: VHenryArt. Licensed under the Creative Commons Attribution-Share Alike 4.0 International license. http://en.wikipedia.org/wiki/File:Obstetric_Fistula_Locations_Diagram.png