Background and study aims: It is generally believed that making a correct histological diagnosis of colitis at colonoscopy requires segmental mucosal biopsies, information on the endoscopic features, and clinical data. This prospective study was carried out to determine the essential parameters required for an accurate diagnosis of colitis.
Patients and methods: Two hundred consecutive patients with suspected or established colitis who underwent colonoscopy were prospectively examined. A double biopsy was taken at a macroscopic site of typical inflammation, or, if no abnormalities could be found, from normal mucosa. In addition, segmental biopsies were obtained. Endoscopic features and the patient's clinical history and symptoms were recorded. Histology was analyzed by providing the pathologist with the double-biopsy sample, segmental biopsies, and endoscopic and clinical information in a segmental fashion. Changes in the diagnoses were noted after each step of the analysis.
Results: Colitis was diagnosed in 152 patients (76 %). Double-biopsy examination provided the correct final diagnosis in 66 % of cases. After assessment of the segmental biopsies, the diagnosis had to be changed in 26 % of cases. Information on the endoscopic features altered the diagnosis in 2.5 %. Finally, the diagnosis was changed in an additional 5.5 % of cases after clinical data (the patient's history and symptoms) had been provided.
Conclusions: Segmental biopsy specimens are essential for the differential diagnosis of intestinal inflammation. Information on the endoscopic features and clinical data are useful in differentiating some forms of colitis.