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This information was reviewed and approved by Tilman L. Koelsch, MD (9/1/2015).

What is a colon transit study?

Your doctor has suggested you have a colon transit study (sitzmark study) as part of the evaluation at National Jewish Health. A colon transit study is a diagnostic test that will allow your doctor to evaluate the function of your colon. The colon is the lower portion of the GI tract and is about 5 feet long. The colon transports food from your small intestine to your rectum. This study can help your doctor determine a diagnosis and the best treatment for you.


How do you get ready for the test?

Planning ahead:

  • Purchase the supply of Sitzmark capsules you will be taking for the study. You will get a prescription for the capsules. You can get these at the National Jewish Health pharmacy.

  • You will not be able to take a laxative during the days you are doing the test. You should also not take any laxatives for two days before this exam. There should be no bowel preparation/colon cleansing before this exam.

  • You can take a fiber supplement product containing psyllium such as Metamucil or Benefiber.

Begin the test when you have a bowel movement:

  • Take the first Sitzmark capsule on day 1 day at 9 a.m. or at the same time you eat breakfast. Day 1 will be on a Tuesday or Friday.

  • You will take 1 Sitzmark capsule day 2 and day 3 at 9 a.m. (or at the same time you took the capsule on day 1).

  • On the fourth day after you start taking the capsules you will have an abdominal x-ray at about the same time you have been taking the capsules.

  • You may need to come back for an abdominal x-ray on the seventh day after you start taking the capsules. You will be informed after the x-ray on the fourth day.


What is done during the test?

The colon transit study will take 4 or 7 days to complete. You will take 1 Sitzmark capsule every day for 3 days. On the fourth day you will come to National Jewish Health for an x-ray of your abdomen.

The x-ray of your abdomen does not hurt. The radiology technologist will explain the x-ray to you before you start. Ask questions if you don’t understand. You may need to come back on the seventh day for another abdominal x-ray.

Let the technologist know if you are pregnant or nursing.
The doctor will review the test results and discuss them with you at a later date.

Remember to schedule the abdominal x-ray for the colon transit study 4 and 7 days after you take the first capsule.


How long will the test take?

The entire Colon Transit Study takes 4 or 7 days after you take the first capsule. When you come to National Jewish Health the abdominal X-ray will take about 30 minutes. 


How do you get to your test?

On the day of your scheduled test, check in at the Front Desk. If you have questions please call 303.398.1355.


This information has been approved by Tilman L. Koelsch, MD (September 2015).