Diagnosis of interstitial cystitis
A clinical, endoscopic and pathologic approach
Criteria for the diagnosis of a disease are needed if the disease may be confused with other diseases due to overlapping features. This was clearly the case for interstitial cystitis (IC) 30 years ago. Therefore, the National Institute of Diabetes and Digestive and Kidney Disease (NIDDK) formulated criteria for diagnosis in 1987 . The NIDDK criteria were specifically designed for research. For research purposes, most scientists will only accept “certain” diagnoses. Consequently, patients had to fulfill many requirements for inclusion, while many conditions existed that excluded patients from a diagnosis. Research criteria, therefore, have a high specificity by design and, consequently, a low sensitivity. The definition of research criteria by the NIDDK can be considered to have been a milestone in the facilitation of research of IC. The NIDDK criteria have been widely used ever since, not only for research but also in clinical settings.