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C. diff Testing Test

C. diff testing checks a sample of your stool for signs of an infection with a bacteria called C. diff. It helps find out if C. diff is causing your diarrhea.

What this test measures

C. diff testing checks a sample of your stool (poop) for signs of an infection with a bacteria called C. diff. It may look for toxins, toxin genes, or GDH antigens from the bacteria.

What your results mean

Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.

Higher-than-normal results

A positive (abnormal) test result may mean that toxins from C. diff bacteria are causing your symptoms. You may be diagnosed with C. diff if your tests show that your sample contained C. diff toxin genes or C. diff toxins.

Lower-than-normal results

A negative (normal) test result generally means that no signs of a C. diff infection were found in your sample. Your symptoms are probably caused by something else.

Frequently asked questions

What is C. diff?

C. diff is a bacteria that can cause an infection in your large intestine. It is also called C. difficile or Clostridioides difficile.

How do you get a C. diff infection?

You can get the bacteria by touching a contaminated surface and then touching your mouth. Most infections happen while taking certain antibiotics or within weeks after.

What symptoms does a C. diff infection cause?

It can cause symptoms ranging from mild diarrhea to serious dehydration and colitis (inflammation in your colon). In rare cases, it can become life-threatening.

What do the different C. diff tests check for?

Some tests check for toxins, some check for genes from toxin-producing C. diff, and others check for GDH antigens. Your provider may order more than one type.

What happens if I am diagnosed with a C. diff infection?

Your provider may tell you to stop taking the antibiotic you are on and prescribe a different antibiotic that targets C. diff. You may also need fluids if dehydrated.

Related lab tests

Sources

Last updated . Information is aggregated from official public sources and is not a substitute for professional medical care.