The following may be helpful in diagnosing interstitial cystitis:
- Medical history and bladder diary. Your doctor will ask you to describe your symptoms and may ask you to keep a bladder diary, recording the volume of fluids you drink and the volume of urine you pass.
- Pelvic exam. During a pelvic exam, your doctor examines your external genitals, vagina and cervix and feels your abdomen to assess your internal pelvic organs. Your doctor may also examine your anus and rectum.
- Urine test. A sample of your urine is analyzed for signs of a urinary tract infection.
- Cystoscopy. Your doctor inserts a thin tube with a tiny camera (cystoscope) through the urethra, showing the lining of your bladder. Your doctor may also inject liquid into your bladder to measure your bladder capacity. Your doctor may perform this procedure, known as hydrodistention, after you've been numbed with an anesthetic medication to make you more comfortable.
- Biopsy. During cystoscopy under anesthesia, your doctor may remove a sample of tissue (biopsy) from the bladder and the urethra for examination under a microscope. This is to check for bladder cancer and other rare causes of bladder pain.
- Urine cytology. Your doctor collects a urine sample and examines the cells to help rule out cancer.
- Potassium sensitivity test. Your doctor places (instills) two solutions — water and potassium chloride — into your bladder, one at a time. You're asked to rate on a scale of 0 to 5 the pain and urgency you feel after each solution is instilled. If you feel noticeably more pain or urgency with the potassium solution than with the water, your doctor may diagnose interstitial cystitis. People with normal bladders can't tell the difference between the two solutions.