trial impact

Lab Investigation in IC

Diagnostic evaluation

None of the diagnostic tests available can exclusively diagnose interstitial cystitis (IC). These tests along with history and physical examination assist in excluding conditions which have a similar symptom profile as the IC, and thereby aid in early diagnosis of the syndrome. The diagnostic tools routinely used as discussed below.

Voiding Dairy

The voiding dairy is an important tool to determine baseline symptoms. All the patients are asked to maintain a voiding dairy, which records daily fluid intake and urine output. Certain foods such as alcohol, caffeine and carbonated drinks can cause irritation of the bladder. Awareness on this helps in exclusion of such food items and prevent worsening of symptoms. This also helps to evaluate the effectiveness of therapy.2


  • Urinalysis in a patient with IC is usually within normal limits.
  • Urine culture reports are ideally negative in a patient with IC.
  • Few patients may, however, show evidence of microscopic haematuria and pyuria.
  • There is a limited role of urinalysis in patients with IC, as cytology findings cannot definitively diagnosis this syndrome. 1,

Potassium Sensitivity Test

  • It is a highly specific diagnostic test in patients with IC to identify the bladder origin of the symptoms.
  • Data available from published studies show that almost 80% of patients with IC have positive potassium sensitivity test.
  • This test is based on the hypothesis of dysfunctional bladder epithelium causing increased permeability to certain intravesical constituents including potassium.
  • The test rates the degree of pain or urgency in a patient after instillation of sterile water into the bladder. The degree of pain is rated on a scale of zero to five.
  • The test is positive when an increase in the baseline score by two or more points on instillation of potassium chloride solution is noted.
  • A patient with IC experiences severe acute pain during the procedure.
  • A patient without IC experiences no pain during the procedure.
  • False positive results are seen in patients with urinary tract infections and radiation cystitis.
  • A positive PST has a correlation with high PUF scores. 2-5

Urodynamic Tests

  • Urodynamic studies are not routinely recommended for evaluation of IC.
  • There are no specific and consistent urodynamic findings in patients with IC.
  • Patients with IC show symptoms of pain with bladder filling and a small volume void sensation during cystometrogram (CMG). However, a reduction in bladder capacity is only noted in advanced cases of IC.
  • Bladder compliance, volitional bladder contractions, pressure flow studies and uroflow studies are normal in patients with IC.
  • Increased activity is seen with pain caused by bladder filling during sphincter electromyography testing.
  • Urodynamic studies help in distinguishing cases of painful voiding or overactive bladder from IC. 1,3,4


  • Cystoscopy is the most important tool in the assessment of patients with IC.
  • It is usually done under anaesthesia as there is a tendency for bladder hypersensitivity in patients with IC.
  • While majority of the patients experience a temporary relief of symptoms after the procedure, it gets aggravated in the remaining few. Some of the diagnostic findings are diminished bladder capacity under anaesthesia and evidence of Hunner ulcer. 1,2,6

Cystoscopy with Hydrodistention

  • Cystoscopy with hydrodistention of the bladder is no longer used to diagnose IC, owing to the presence of classic Hunner ulcers in less than 10% of IC patients.
  • Major indications for this test are haematuria and abnormal cytology reports.
  • Findings in patients with classic or ulcerative IC are glomerulations, submucosal haemorrhages and fissures with bleeding. Scarring of the bladder wall is seen in cases with reduced bladder capacity.
  • There is no evidence of ulcers or scars in the nonulcerative IC patients and the bladder capacity is noted to be more than 400 mL.
  • History of pregnancy, UTI and prior rupture during distension are contraindications for this procedure. 1-3, 6

Intravesical Anaesthetic Challenge Test

  • This relatively new diagnostic test may help in identifying bladder as the source of pain in patients presenting with symptoms of IC. It is based on the principle that the instillation of an anaesthetic lidocaine/bicarbonate solution in the bladder of a patient with IC would result in reduction of pain. 1,2

Bladder Biopsy

  • This procedure is primarily based on the proposition that there is an increased density of mast cells in patients with IC.
  • It is a nonmandatory test in the clinical work-up in patients with IC.
  • Biopsies are primarily performed when there is a suspicion for malignancy, premalignant lesions and other varieties of cystitis.
  • In patients with IC, pancystitis with heavy mast cell infiltration of the bladder wall is seen.
  • The histological features show an increased numbers of mast cells in the detrusor muscle or submucosa.
  • Chronic inflammatory infiltration of the lamina propria is seen with fibrosis of the detrusor or lamina propria. 1,2
  1. Evans RJ. Pathophysiology and clinical presentation of interstitial cystitis. Avd Stud Pharm. 2005;8-14.
  2. Carr LK, Corocs J, Njckel C, Teichman J. Diagnosis of Intersitial cystitis June 2007. Can Urol Assoc J. 2009;3(1):81-86.
  3. Heck BN. Interstitial cystitis:Enhancing early identification in primary care settings. JNP. 2007;3(8):509-519.
  4. Panzera AK. Interstitial cystitis/Painful bladder syndrome. Urol Nurs. 2007;27(1):13-19.
  5. Parsons CL, Dell J, Stanford EJ, et al. Increased prevalence of interstitial cystitits: Previously unrecognized urologic ang gynecologic cases identified using a new symptom questionnaire and intravesical potassium sensitivity. Urology. 2002;60:573-578.
  6. Teichman JMH, Parsons CL. Contemporary clincal presentation of interstitial cystitis. Urology. 2007;69(4A):41-47.