Bowel Transit Time
How It Is Done
Your doctor will give you one or more gel capsules filled with markers that will show up on an X-ray. Follow your doctor's instructions about when to take the
capsules. You may take only one capsule. Or you may be told to take one at a certain time for 2 or 3 days in a row.
You will then have X-rays taken of your belly. These are usually done on day 5. The percentage of markers that show up on the X-ray tells your doctor if you have a normal bowel transit time.
How It Feels
Bowel transit time tests do not cause
You will not feel discomfort from the X-rays used for the test. The X-ray table may feel hard and the room may be cool. You may
find that the positions you need to hold are uncomfortable.
This test is not recommended if you are
pregnant because the radiation from the X-ray can harm your developing baby
A bowel transit time test measures how
long it takes for food to travel through the
digestive tract .
Bowel transit time depends on what types of food
you eat and how much you drink. Different people have different bowel transit
Bowel transit time1
Fewer than 20% of the markers show up on an X-ray after 5 days (120 hours).
More than 20% of the markers show up on an X-ray after 5 days (120 hours).
What Affects the Test
You may have an abnormal bowel
transit time if you:
- Have an infection in your
- Do not drink enough fluids (dehydration).
- Have a disease, such as a
narrowing (stricture) in your intestine, an underactive thyroid gland (hypothyroidism),
- Are eating less
than you usually do or you are eating different kinds of food than
- Take medicines, such as cold medicines, iron, or medicine
used to control blood pressure and pain.
What To Think About
- Bowel transit time also can be done using a dye capsule. You swallow a capsule containing a bright red dye and measure the amount of time until you see the red color appear in your stool. You may also measure the time needed for all of the dye to pass through your colon.
- Many doctors do not think that bowel transit time testing
is useful. Different people have different bowel transit times on different
- This test is not recommended if you are or might be
- You can usually speed up bowel transit time if you increase
the amount of fruits, vegetables, and whole grains that you eat each day. For
more information, see the topic
- It is possible to have a
daily bowel movement but still have a slow bowel transit time.