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White Blood Cell (Stool)

Does this test have other names?

Stool white blood cell test, fecal leukocyte (LOO-koh-site) test, FLT

What is this test?

This test looks for white blood cells in your stool. This can help your healthcare provider diagnose the cause of inflammatory diarrhea.

White blood cells, also called leukocytes, are immune system cells that can show up in the stool if you have inflammatory diarrhea. This type of diarrhea may be a symptom of an infection caused by bacteria such as shigella, Clostridium difficile, campylobacter, or salmonella. It may also occur in inflammatory bowel disease, such as Crohn's disease or ulcerative colitis. 

Why do I need this test?

You might have this test if you have inflammatory diarrhea. Symptoms may include:

  • Numerous small loose or watery stools

  • Blood or mucus in the stool

  • Severe cramping or pain in your belly (abdomen)

  • Fever

What other tests might I have along with this test?

Your healthcare provider may order other tests that look at the stool for:

  • Lactoferrin or calprotectin, which are substances made by certain white blood cells

  • Parasites and their eggs (ova)

  • Toxins

  • Blood (hemoccult test)

Your provider may also order a stool culture. For this test, bacteria in a stool sample are encouraged to grow in the lab to see if an infection is present. 

What do my test results mean?

A result for a lab test may be affected by many things, including the method the laboratory uses to do the test.  If your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your healthcare provider.

White blood cells in the stool may mean that you have inflammation in your digestive tract. But a negative result doesn't rule out a problem. Some people with these illnesses don't have white blood cells in their stool. 

How is this test done?

Your healthcare provider will give you a special container with a tightly fitting lid to place the stool sample in. If you aren't able to produce a stool sample, your provider may collect a sample by inserting a swab into your rectum.

What might affect my test results?

Urine or toilet paper may contaminate the sample, affecting the results. Drinking milk can affect the results.

How do I get ready for this test?

You don't need to prepare for this test, but it's a good idea to tell the healthcare provider about other health problems you may have. Be sure your provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illicit drugs you may use. 

Medical Reviewers:

  • Hanrahan, John, MD
  • Sather, Rita, RN