Indigotindisulfonic acid

Indigotindisulfonic acid is a blue-colored dye with a variety of uses. Its salt form, indigotindisulfonate sodium, is also known as indigo carmine, indigotine or FD&C Blue #2. This compound is an acid-base indicator and is used in the production of food colorants and pH tests. Indigotindisulfonic acid is used in clinical medicine to determine patency of the urinary collecting system, and to assist in specific surgical procedures such as cystourethroscopy. In 2022, the FDA approved the intravenous use of indigotindisulfonate sodium to aid in visualizing ureter integrity in cystoscopic assessments.

The main application of indigotindisulfonic acid is localizing and visualizing ureteral orifices during cystoscopy and ureteral catheterization procedures . Indigotindisulfonate sodium (salt form) is indicated for use as a visualization aid in the cystoscopic assessment of the integrity of the ureters in adults following urological and gynecological open, robotic, or endoscopic surgical procedures.