Stool Test: Fecal Blood

What Are Stool Tests?

Testing a stool sample can help doctors find out what's going on when someone has a problem in the stomach, intestines, rectum, or other part of the gastrointestinal (GI) system.

Unlike most other lab tests, parents might need to collect the stool (feces or poop) sample for the test (also called a fecal test). The doctor or lab will give instructions on how to do this.

What Is a Fecal Occult Blood Test?

The fecal (FEE-kul) occult blood test checks for blood in the poop.

Why Are Fecal Occult Blood Tests Done?

A fecal test can find hidden (occult) blood in the stool that can’t be seen by the naked eye. The blood may come from any part of the digestive tract, from the esophagus to the rectum and anus (where poop comes out). Sometimes, it can come from swallowed blood if a child has had bleeding from the mouth, throat, or nose.

Doctors may order a fecal occult blood test to look for blood in the poop from things such as:

• allergies or inflammation
• gastrointestinal infection caused by bacteria, viruses, or parasites
• bleeding in the GI tract from ulcers and other problems
• polyps (abnormal growths in mucous membranes, like the colon)

For a week before the test, your child may be asked to avoid some types of foods and medicines (such as aspirin and anti-inflammatory drugs like ibuprofen), and vitamin C supplements.

How Is the Test Done?

The doctor or lab technician smears some of the sample onto special paper, then puts a chemical solution called guaiac (GWY-ak) on it. If the paper turns blue, there's blood in the stool.

What if I Have Questions?

If you have questions about the fecal test or what the test results mean, talk to your doctor.