Colonic Transit Testing
What is colonic transit?
Colonic transit measures the time it takes a substance to enter the colon and move completely through the colon to be excreted. Prolonged colonic transit may be a cause of chronic constipation.
How is it tested?
To measure colonic transit, your physician will have you swallow a capsule containing a specific number of tiny markers (usually 24). These markers are clearly visible on X-ray. You will then have a series of abdominal X-rays, at specified time intervals, to determine how rapidly the markers are moving through your colon. The radiologist will count the number of markers in each segment of the colon, and compare this to established normal ranges. If the markers move more slowly than is normal, then your physician will know that a delayed colonic transit is contributing to your constipation symptoms, and may prescribe dietary changes and medications to address this problem.
Where is the test performed?
Instructions as to when to swallow the markers and have the X-rays taken are provided in the GI Physiology Lab of the Medical Procedures Unit, on the second floor of University of Michigan Hospital. The X-rays may be obtained at the hospital, or at another facility closer to your home. The technician providing the instructions will advise you as to this.
What preparation is needed?
There is no preparation required for this test. However, it is necessary to DISCONTINUE ANY LAXATIVES for 1 week before swallowing the markers and until the test is completed. You may continue taking fiber supplements throughout the test. You should continue your normal diet and medications during the test.
When will I have the results?
The results will be reported to the physician who ordered the test, and that physician will communicate the results to you (probably at your next office visit).
Click here for a Colonic Transit Test Diary Sheet
Information provided by the Michigan Bowel Control Program, May 2006