Diagnosis of Constipation

How do doctors find the cause of constipation?

Doctors use your medical and family history, a physical exam, or medical tests to diagnose and find the cause of your constipation.

Medical and family history

Your doctor will ask you questions about your medical history, such as

  • whether you have ever had surgery to your digestive tract
  • if you have recently lost or gained weight
  • if you have a history of anemia

Your doctor also is likely to ask questions about your symptoms, such as

  • How often do you have a bowel movement?
  • How long have you had symptoms?
  • What do your stools look like?
  • Do your stools have red streaks in them?
  • Are there streaks of blood on your toilet paper when you wipe?

Your doctor is likely to ask questions about your routines, such as

You may want to track your bowel movements and what your stools look like for several days or weeks before your doctor’s visit. Write down or record the information so you can share it with your doctor.

If you’ve been constipated a long time, your health care professional may ask whether anyone in your family has a history of conditions that may cause long-lasting constipation, such as

Physical exam

During a physical exam, a health care professional may

  • check your blood pressure, temperature, and heart rate
  • check for dehydration
  • use a stethoscope to listen to sounds in your abdomen
  • check your abdomen for
    • swelling
    • tenderness or pain
    • masses, or lumps
  • perform a rectal exam
An older man gets his blood pressure taken by a health care professional.
A doctor may use information from your medical and family history, a physical exam, or tests to find the cause of your constipation.

What medical tests do doctors use to find the cause of constipation?

Depending on your symptoms and health, your doctor may first try a treatment to improve your symptoms before using tests.

Lab tests

Your doctor may use one or more of the following lab tests to look for signs of certain diseases and conditions that may be causing your constipation

Endoscopy

Your doctor may perform an endoscopy to look inside your anus, rectum, and colon for signs of problems in your lower digestive tract. Endoscopies for constipation include

During these two tests, your doctor may also perform a biopsy. A biopsy is a procedure that involves taking small pieces of tissue and examining them under a microscope. A doctor can use a biopsy to look for signs of cancer or other problems.

Colorectal transit studies

Your doctor may use bowel function tests called colorectal transit studies to see how well your stool moves through your colon.

  • Radiopaque markers—an x-ray that tracks radioactive markers while they pass through your digestive system. You swallow capsules with the markers, which take about 3 to 7 days to come out with a bowel movement.
  • Scintigraphy—a test that involves eating a meal with a small dose of a radioactive substance. Your doctor tracks the substance using special computers and cameras as the substance passes through your intestines.

Other bowel function tests

Your doctor may also use one or more of the following tests to look for signs of certain diseases and conditions that may be causing your constipation

  • defecography—an x-ray of the area around the anus and rectum to see how well you can hold and release stool
  • anorectal manometry—a test to check how sensitive your rectum is, how well it works, and how well the anal sphincters work
  • balloon expulsion test—a test that involves pushing a small water balloon from your rectum to see if you have a problem pushing out stool

Imaging tests

To look for other problems that may be causing your constipation, your doctor may perform an imaging test such as

May 2018
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This content is provided as a service of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health. The NIDDK translates and disseminates research findings through its clearinghouses and education programs to increase knowledge and understanding about health and disease among patients, health professionals, and the public. Content produced by the NIDDK is carefully reviewed by NIDDK scientists and other experts.