Peritoneal aspiration cytology as a diagnostic aid in acute appendicitis

A total of 110 consecutive patients presenting to one surgical firm with suspected acute appendicitis underwent peritoneal aspiration cytology. Aspiration was successful in 108 patients and 44 were positive. Patients with a positive result underwent emergency surgery; 42 had histologically proven acute appendicitis and two peritonitis of other causes. Seven patients with a negative result underwent appendicectomy; four had acute appendicitis and three a normal appendix. Peritoneal aspiration cytology had a sensitivity for acute appendicitis of 91 per cent and a specificity of 94 per cent. The positive predictive value of the test was 95 per cent and the negative predictive value 94 per cent. The negative appendicectomy rate was 10 per cent overall and 11 per cent in women of reproductive age. Peritoneal aspiration cytology is a useful diagnostic test in the management of patients with suspected acute appendicitis.