What is a Potassium Sensitivity Test?

A potassium sensitivity test is an investigative medical test that urologists often recommend to patients they suspect may be suffering from interstitial cystitis (IC). Interstitial cystitis is a condition of the bladder that causes recurring symptoms similar to urinary tract infections, but the symptoms can’t be explained because no bacterial infection is found. There are several diagnostic tests that can be performed to help determine the cause of pelvic and urinary pain and discomfort, and a potassium sensitivity test is one simple test that can be used to help determine if IC is the cause of symptoms.

A doctor may recommend a test for potassium sensitivity if a patient presents with symptoms similar to a urinary tract infection on recurring occasions and laboratory urine cultures show no bacterial infection. The test can be administered in the office and performed by a registered nurse. It takes only 20 to 30 minutes to complete and requires no anesthesia.

A potassium sensitivity test involves introducing the bladder to two sterile solutions via injection into a catheter. Both water and potassium solutions are injected separately into the catheter and then comparisons are made based on whether or not the patient feels any pain, burning or other discomfort while the solution remains in the bladder or afterwards. If a patient has IC, they often develop the same pain, urgency, or discomfort they feel on a recurring basis because of the potassium.

This test can be useful in diagnosing or ruling out IC because patients with IC are believed to have bladders with damaged lining. As the natural potassium in the urine passes through the kidney and into the bladder, the potassium seeps into cracks in the damaged bladder lining causing the classic symptoms of urinary urgency, frequency, pain and discomfort. A test for potassium sensitivity therefore helps determine if in fact potassium is causing the symptoms and helps determine if a visual examination of the bladder, called a cystoscopy, is necessary.

Many doctors feel that a potassium sensitivity test is useful in the diagnosis of certain urinary conditions, while others are still convinced cystoscopy is more definitive. Individual opinions will vary from doctor to doctor, but either test is simple and involves very little risk. Infection is the greatest risk involved with a potassium sensitivity test and in the event the patient does experience pain and discomfort with the introduction to potassium, a “rescue” rinse can be used to relieve the pain.