Interobserver variation in the radiographic diagnosis of gastric ulcer. Gastroenterologists' guesses as to level of interobserver variation.

A total of 156 double contrast barium examinations were independently interpreted by two observers for the presence of gastric ulcer. The observed agreement between the two readings was 93 per cent, and after adjusting for the expected chance agreement a kappa value of 0.73 was obtained. At the first reading 4 ulcers, and at the second reading 8 ulcers were interpreted as malignant. None of these interpretations agreed. In a questionnaire study it was demonstrated that gastroenterologists had a realistic impression of the level of agreement in the radiographic detection of gastric ulcer.