Volume 9, Number 1Review ArticlesDiagnosis of Interstitial Cystitis/ Painful Bladder Syndrome in Patients With Overactive Bladder SymptomsDiagnosis UpdateScott MacDiarmidPeter K SandOveractive bladder (OAB) and interstitial cystitis (IC) have similar symptoms, including urinary urgency/frequency and nocturia, making them difficult to differentiate on the basis of clinical presentation alone. Both conditions may represent a clinical manifestation of a hypersensitive bladder and should be included in the differential diagnosis for patients who present with urgency/ frequency. It is especially important that IC be considered in patients with OAB that is refractory to treatment. The proposed diagnostic framework may be useful for differentiating IC from OAB and for facilitating appropriate treatment. [Rev Urol. 2007;9(1):9-16]Overactive bladderInterstitial cystitisPainful bladder syndrome