Clostridium Difficile Toxins

Test Overview

Clostridium difficile (C. difficile) are bacteria that live in your large intestine, or colon, all the time. They usually don't cause problems. But sometimes, something causes the bacteria to grow. When there are too many of them, they release harmful substances called toxins.

When the toxins are released, the colon becomes irritated and swollen. This problem is called C. difficile colitis.

C. difficile can be passed from person to person. But the infection is most common in people who take antibiotics or have taken them recently. Antibiotics are drugs used to kill bacteria that cause infection. But they also can destroy some of the normal "good" bacteria in the colon that keep C. difficile from growing and releasing toxins.

C. difficile is also common in older people who are in hospitals and nursing homes and in people who are getting chemotherapy for cancer.

The C. difficile toxins test looks at a stool sample to see if those toxins are present. A positive result means you need treatment for colitis.

Why It Is Done

The test is done to see if diarrhea that won't go away was caused by C. difficile toxins.

How To Prepare

You do not need to do anything special to prepare for this test.

Tell your doctor if you have recently taken antibiotics.

Talk to your doctor about any concerns you have about the need for the test, its risks, how it will be done, or what the results may mean. To help you understand the importance of this test, fill out the medical test information form .

How It Is Done

Stool samples can be collected at home. Or you may need to go to your doctor's office, a medical clinic, or the hospital. If you collect the sample at home, you may be given a special container.

You may need to collect more than one sample. Follow the same steps for each sample.

To collect the sample:

  • Urinate before you collect the stool. That way, you won't get any urine in the stool sample. Do not urinate while you pass the stool.
  • Wash your hands before you collect the sample.
  • Put on gloves before handling your stool. Stool can contain germs that spread infection. Wash your hands before putting on your gloves and after you take them off.
  • Pass stool (but no urine) into a dry container. You may be given a plastic basin that you can place under the toilet seat to catch the stool.
    • For diarrhea, a large plastic bag taped to the toilet seat may make the collection process easier. The bag is then placed in a plastic container.
    • Do not collect the sample from the toilet bowl.
    • Do not mix toilet paper, water, or soap with the sample.
  • Place the lid on the container. Label it with your name, your doctor's name, and the date the stool was collected.

Take the sample to your doctor's office or the lab as soon as you can. You may need to take your sample to the lab within a certain time, usually within 30 minutes or less of collecting it. Tell your doctor if you think you may have trouble getting the sample to the lab on time.

Samples from babies and young children may be taken from diapers (if the stool does not have urine mixed with it). Or a narrow tube may be put into the baby's rectum while you hold the baby on your lap.

How It Feels

Most people do not feel pain when they collect a stool sample.


There is no chance for problems while collecting a stool sample.

Be sure to wear gloves when you collect the sample. Wash your hands with soap and clean, running water before and after you collect the sample. This will help protect you from spreading an infection. Do not use alcohol-based hand sanitizer instead of handwashing. Sanitizer will not kill C. difficile.


The test is done to see if diarrhea that won't go away was caused by C. difficile toxins.

There are several types of tests for this toxin. Depending on the test used, results may take several hours or a day or two.

C. difficile toxins in stoolfootnote 1

Normal (negative)

The stool sample does not contain C. difficile toxin.

Abnormal (positive)

The stool sample contains C. difficile toxin.

What Affects the Test

The results of the test may not be helpful if:

  • You do not have a large enough sample.
  • You do not turn in the stool sample soon enough after you collect it.

What To Think About

C. difficile colitis can cause serious problems. If you test positive, you will need treatment.



  1. Pagana KD, Pagana TJ (2010). Mosby's Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.


Current as of: September 23, 2020

Author: Healthwise Staff
Medical Review:
Kathleen Romito MD - Family Medicine
E. Gregory Thompson MD - Internal Medicine
Adam Husney MD - Family Medicine
Martin J. Gabica MD - Family Medicine
Arvydas D. Vanagunas MD - Gastroenterology

Is it an emergency?

If you or someone in your care has chest pains, difficulty breathing, or severe bleeding, it could be a life-threatening emergency. Call 9-1-1 or the local emergency number immediately.
If you are concerned about a possible poisoning or exposure to a toxic substance, call Poison Control now at 1-800-567-8911.

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