Potassium test

Potassium test is a diagnostic technique that allows you to identify increased permeability of the bladder mucosa, which may indicate a lack of urothelial glycosaminoglycans, which often accompanies interstitial cystitis and chronic pelvic pain syndrome. 
The potassium test is considered positive when the pain intensifies when a potassium chloride solution is injected into the bladder.
This test can be performed on an outpatient basis, does not require much time, and is minimally invasive.
Potassium test method:
  1. In the first stage, 40 ml of sterile water is injected into the bladder. After this, the patient evaluates pain sensations and the appearance of an imperative urge on a five-point scale within 5 minutes.
  2. Then 40 ml of potassium chloride solution is injected into the bladder. Also, within 5 minutes, the patient evaluates pain symptoms and the presence of an imperative urge on a five-point scale.
The patient alternately, for each solution, determines the severity of pain and urge. The test is based on the theory of disruption of the integrity of the bladder mucosa, in particular the glycosaminoglycan layer, and the penetration of an aggressive urinary environment (and in this case, potassium) into the thickness of the bladder wall, which causes irritation of the nerve endings.
Parsons performed a potassium test on 1,500 patients with IC, and 80% tested positive. In the healthy control group, only 4% had a positive potassium test (Parsons C.L. et al 2002). According to Chambers G.K. et al (1999), the sensitivity of the potassium test is 69.5%, specificity 59%. Given these characteristics, the test is not included in the NIH/NIDDK exclusion criteria and cannot be recommended as the only diagnostic test. The test results should be considered in conjunction with the clinical picture and cystoscopic data.