Stool Test: Giardia

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 stool culture or fecal test). The doctor or lab will give instructions on how to do this.

Depending on the type of test, results can be back in 24–48 hours or take 3–4 days.

What Is a Giardia Test?

The Giardia lamblia parasite is a common cause of diarrhea. In someone with an infection, they live in the GI system and leave the body in poop.

A Giardia (jee-ARE-dee-uh) test checks a stool sample for the parasites.

Why Are Giardia Tests Done?

Doctors order Giardia tests to diagnose giardiasis (jee-are-DYE-uh-sis), the digestive tract illness caused by Giardia lamblia.

Symptoms of an infection include:

• watery diarrhea
• belly pain
• lots of intestinal gas
• appetite loss
• nausea or vomiting

A Giardia test also can see if treatment for giardiasis has worked.

Sometimes, doctors also order an ova and parasite (O&P) test, which checks a stool sample for parasites. The Giardia test can better find Giardia lamblia than the O&P test, but can't identify other parasites that might be causing the GI problems.

If possible, your child may be asked to avoid some foods and treatments for 2 weeks before the test, including:

• antidiarrheal drugs
• antibiotics and antiparasite drugs
• enemas

How Is the Test Done?

At the lab, a technician tests the stool sample for signs of the Giardia lamblia parasite. The test can find only this parasite, so the doctor may order other tests to make a diagnosis.

What if I Have Questions?

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