Diagnosing Constipation

Tests Are Not Usually Needed To Diagnose Constipation

The majority of adults will experience constipation at some point in their lives. In most cases, a diagnosis of constipation by a physician isn't necessary, and constipation can be treated at home with non-invasive methods. Sometimes a physician may be consulted on the type of treatment that would be the safest and most effective, but a formal work-up to diagnose constipation would not be done. This would be especially true for young people who have no history of constipation or digestive disease.

For older people, or for those who have more complex medical histories, constipation may be a symptom of a more serious illness. In addition to treating the symptoms of constipation, further testing and treatment of the underlying cause is extremely important.

People with inflammatory bowel disease (IBD) are more likely to experience diarrhea, but, rarely, people with Crohn's disease may also experience constipation. Constipation in Crohn's disease could be due to a stricture, an obstruction, or disease in the rectum.

History of Constipation

A first step in diagnosing constipation would be to find out more from the patient about the digestive signs and symptoms they are experiencing. Some questions a physician might ask include:
  • How often do you have a bowel movement?
  • What is the consistency of your bowel movements (such as hard or lumpy)?
  • Do you ever ignore the urge to have a bowel movement?
  • Do you strain while having a bowel movement?
  • What is your normal diet?
  • Do you experience pain or other symptoms before or after a bowel movement?
  • How often do you exercise?

A physician may also ask questions regarding a general health history, such as the presence of any other diseases or a history of abdominal surgery. Some questions may seem unrelated to the digestive system, but having a complete picture can help pinpoint the cause of constipation.

Physical Exam

One common test that is used during the diagnosis of constipation would be a digital rectal exam. During this test, the physician will put on a pair of gloves, lubricate the index finger, and insert that finger into the anus. This exam is often done quickly to minimize discomfort to the patient, but a physician can tell a great deal about the anus and the condition of the anal sphincter during this brief test. In addition, if the physician finds blood, mucus, or stool in the rectum, that can provide some clues about what is going on inside the rectum. If there is something found amiss, a colonoscopy may be done to further determine what is causing the constipation.

Diagnosing Chronic Constipation

Other tests used in the diagnosis of chronic constipation include:

  • Blood tests, to rule out certain reasons for constipation, such as thyroid disease.
  • Colonic transit rate test, which shows how long it takes food to move through the intestines.
  • Barium x-ray, which uses contrast dye to make the colon more visible and show any irregularities, such as a blockage.
  • Endoscopy, such as sigmoidoscopy and colonoscopy, which uses a camera and gives the most complete look at the lower gastrointestinal tract.


National Digestive Diseases Information Clearinghouse (NDDIC). "Constipation." National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) July 2007. 08 Sept 2011.

The Nemours Foundation. "Inflammatory Bowel Disease." KidsHealth.org 2011. 08 Sept 2011.

Ternent CA, Bastawrous AL, Morin NA, Ellis CN, Hyman NH, Buie WD, Standards Practice Task Force of The American Society of Colon and Rectal Surgeons. "Practice parameters for the evaluation and management of constipation." Dis Colon Rectum 2007 Dec;50:2013-2022. 08 Sept 2011.

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