In interstitial cystitis workup, which additional studies may be helpful beyond urinalysis and culture?

• A. Bone density scan
• B. Liver function tests
• C. Urethral and vaginal culture
• D. Serum potassium

Answer: (C)

The key idea is that interstitial cystitis is a diagnosis of exclusion, but symptoms can overlap with infections or other genitourinary conditions. Beyond basic urinalysis and urine culture, sampling from other sites helps rule out alternative or coexisting infections that can mimic or accompany bladder pain and frequency. A urethral and vaginal culture can detect infections in those areas—such as urethritis, vaginal infections, or other pathogens—that might explain the symptoms or require targeted treatment. Identifying these helps avoid misdiagnosis and ensures appropriate management.

The other options aren’t aligned with this differential approach. A bone density scan, liver function tests, or serum potassium testing don’t address infections or conditions that could present like interstitial cystitis, so they’re not helpful in distinguishing this syndrome from other genitourinary problems.