Is the potassium sensitivity test a valid and useful test for the diagnosis of interstitial cystitis?

Excerpt

When examining the utility of the potassium chloride test, we must first take a step back and critically examine the value of a “diagnostic” test in what is essentially a clinical syndrome defined by a symptom complex. If a patient has chronic pain associated with the bladder, urinary frequency, and/or a constant sensation of urinary urgency with no discernable cause, we diagnose interstitial cystitis (IC). For the sake of clarity, it should be noted that urgency in this context refers to pain or discomfort with bladder filling, often relieved by emptying, and not the sudden sensation of impending incontinence which would be consistent with a diagnosis of overactive bladder. In essence, once we have ruled out well-characterized pathologic entities, the patient makes the diagnosis of IC by relating the symptoms, much like a patient with impotence makes that diagnosis. Testing for impotence may give clues as to etiology, but we cannot rule out erectile dysfunction in a patient who can’t function sexually by doing a test! A diagnostic test or marker would be very important to the extent that it could be shown to rule out competing etiologies of the symptom set, predict long-term prognosis, and/or change the treatment algorithm by pointing the way toward effective therapies in those who test positive or negative. The literature would suggest that at this juncture, the KCl test fails to meet any of these criteria. …