Constipation in adults

Tests you might need if you have constipation

If you have constipation, your doctor may order some tests to find out what's causing your symptoms.

But most people with constipation don't need any tests. You may have them if your doctor wants to make sure that your constipation isn't because of a more serious medical condition. You'll probably need them only if you have other symptoms as well as being constipated, such as bleeding or losing weight suddenly.

Some of the tests you might have are listed below.

Blood test. You may have a blood test to check that your thyroid gland is working properly. The

thyroid gland
Your thyroid gland is a small organ that sits in your neck, just in front of your windpipe. It sends out a hormone called thyroxine. This acts on receptors within cells. By acting on the receptors it gives the cells a message to speed up their metabolism and work harder.

thyroid is a small gland in your neck. You can become constipated if your thyroid is underactive. To read more, see our information on Underactive thyroid.
A test to see how much calcium you have in your blood. This test helps check for lots of different conditions. And it can give your doctor an idea of how healthy you are in general.
Barium enema. This helps to take an

X-ray
X-rays are pictures taken of the inside of your body. They are done by passing very small amounts of radiation through your body and onto film. X-rays can also be used as a treatment, such as in radiation therapy for cancer.

X-ray of your bowel. A thick, white liquid that contains a chemical called barium is passed through a tube into your

rectum
The rectum is the last six to eight inches of the large intestine, ending with the anus (where you empty your bowels).

rectum. Barium shows up on X-rays, so it helps your doctor see if your bowel is blocked.
Proctogram. This is a bit like a barium enema. You sit on a toilet in the X-ray room. X-rays are taken when you pass the barium in the same way as you would pass a stool.
Colonoscopy. This test is done to check for disease inside your bowel. A doctor puts a tube with a camera on the end (a colonoscope) into your rectum and passes it into your

colon
Your colon is the first 2 metres (6 feet) of your large intestine. During digestion, food travels from your stomach to your small intestine and then to your large intestine. What's not digested then leaves your body as a bowel movement.

colon. We've prepared some extra information for people thinking of having this test. To read more, see Colonoscopy.
A test to measure how well your bowel muscles work. Your doctor may call this anorectal manometry. A thin tube with a balloon on its end is put into your rectum. The balloon is then slowly filled up. This makes the muscles in your rectum and

anus
The anus, which is at the end of the rectum, is where a stool leaves your body when you go to the bathroom. Part of the anus is a muscle that helps you hold in the stool until you are on the toilet.

anus squeeze, and a machine measures how strongly you squeeze. This test shows how well the muscles and nerves in your bowels are working. But this test isn't done often.
A test that shows how well food moves through your bowels. For this test, you swallow some capsules that show up on X-rays. Your doctor can then find out how long it takes for food to pass through your body. But it's rare for people to need this test.

This information was last updated on Jan 07, 2009

This information is for educational use only, and is not a substitute for prompt professional medical advice. Readers should always consult a physician or other professional for advice and treatment.
© BMJ Publishing Group Limited 2009. All rights reserved.

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