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Stool test

A stool test examines the stool (feces). Stool tests are useful for investigating problems in the stomach, intestine or other parts of the digestive system.

Why a stool test is done

A stool test may be done to check for:

  • bleeding inside the gastrointestinal (GI)gastrointestinal (GI)Referring to or having to do with the digestive organs, particularly the stomach, small intestine and large intestine. tract
  • infection (from bacteria, viruses or parasites)
  • digestive problems (such as malabsorption of certain sugars, fats or nutrients)

Screening for colorectal cancer uses stool tests to check for bleeding inside the GI tract. Find out more about screening for colorectal cancer.

What type of stool test is used

There are several different types of stool tests. The type of stool test used depends on why the test is being done and what the doctor is looking for. Some types of stool tests are:

  • gFOBT (guaiac-based fecal occult blood test), which uses a chemical reaction on a paper card to find traces of blood in the stool that you can’t see
  • FIT (fecal immunochemical test), which uses specific antibodies for human blood to find traces of blood in the stool that you can’t see
  • stool culture, which looks for bacteria not normally found in the GI tract that cause infections
  • stool fat testing, which looks for extra fat in the stool to see if the body is having trouble absorbing fat from food

How a stool test is done

Unlike most other lab tests, stool is usually collected at home. Some tips for collecting a stool specimen include:

  • Wear latex gloves as collecting stool can be messy.
  • A number of methods may be used to collect the stool:
    • a hat-shaped plastic container placed over the toilet bowl
    • loosely placed plastic wrap over the toilet bowl
    • plastic wrap to line the diaper (for infants or toddlers)
  • If urine contaminates the stool, another sample will have to be collected.
  • If the stool touches the inside of the toilet, another sample will have to be collected.

At the laboratory, the stool sample is analyzed and examined under a microscope.

What the results mean

In general, normal stool appears brown, soft and well-formed in consistency. It does not contain blood, mucus, pus, harmful bacteria, viruses, fungi or parasites.

Abnormal results may be due to:

  • inflammation of the intestine
  • infection
  • digestive disorders
  • cancer

What happens if a change or abnormality is found

The doctor will decide if more tests, procedures, follow-up care or additional treatment are needed.

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