The time it takes for the food that is eaten to make the journey from the mouth to the anus is known as the bowel transit time. The type of diet affects the bowel transit time. When many foods that have a lot of fiber (whole grains, vegetables, and fruits) are eaten, a more rapid transit time and a heavier, bulkier stool occurs.
How the test is performed
You swallow 2 gelatin capsules filled with carmine red or another food marker with a meal. Then you observe your bowel movements and record how long it takes after the capsules are swallowed until the dye first appears. Keep track of how long it takes for the marker to disappear from the stools.
How to prepare for the test
There are usually no special preparations, however you should follow any diet or other directions from the health care provider.
How the test will feel
Swallowing the gelatin capsules is the only feeling associated with the test.
Why the test is performed
The test offers a way to become more aware of the bowel function. The person can record improvement of transit times as fiber is introduced into the diet.
The bowel transit time varies even in the same person. The first of the color should appear in the stool about 12 to 14 hours after it is taken. The last of the color will appear within 36 to 48 hours.
What abnormal results mean
If the times are much longer, 72 hours or more, it may indicate a slowed bowel function. A high fiber diet should speed the bowel transit time up.
What the risks are
There are no risks.
by Dave R. Roger, M.D.
All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.