A radiopaque marker technique for measuring gastrointestinal transit in subjects with an ileostomy.

We aimed to develop a simple, clinically useful technique for measuring gut transit time in patients with an ileostomy, in order to distinguish easily when patients have fast or slow transit. Seventeen healthy subjects (mean age, 55 years; range, 43-71 years; nine males) who had had a proctocolectomy for ulcerative colitis more than 1 year previously and without small intestinal resection were studied. Subjects were studied on 4 days after an overnight fast, two studies with and two without breakfast. A standard diet was used on all days. Twenty radiopaque markers were given at the start of each study day. Ileostomy effluent was collected over 24 hr and x-rayed to determine the number of retained markers. Studies with breakfast demonstrated greater intrasubject reproducibility. The mean transit time for passage of 50% of markers was 16.6 hr with, and 14.8 hr without, breakfast (p < 0.02). From the data obtained we suggest that the optimum time for taking a single abdominal radiograph in a patient with suspected fast transit is 6 hr after ingestion of markers, while the optimum time for a patient with suspected slow transit is 24 hr.