The stool C. difficile toxin test detects harmful substances produced by the bacterium Clostridium difficile (C. difficile). This infection is a common cause of diarrhea after antibiotic use.
A stool sample is needed. It is sent to a lab to be analyzed. There are several ways to detect C. difficile toxin in the stool sample.
Enzyme immunoassay (EIA) is most often used to detect substances produced by the bacteria. This test is faster than older tests, and simpler to perform. The results are ready in a few hours. However, it is slightly less sensitive than earlier methods. Several stool samples may be needed to get an accurate result.
A newer method is to use PCR to detect the toxin genes. This is the most sensitive and specific test. Results are ready within 1 hour. Only one stool sample is needed.
There are many ways to collect the samples.
Do not mix urine, water, or toilet tissue with the sample.
For children wearing diapers:
You may have this test if your health care provider thinks that diarrhea is caused by the antibiotic medicines you have taken recently. Antibiotics change the balance of bacteria in the colon. This sometimes leads to too much growth of C. difficile.
Diarrhea caused by C. difficile after antibiotic use often occurs in people who are in the hospital. It also can occur in people who have not recently taken antibiotics. This condition is called pseudomembranous colitis.
No C. difficile toxin is detected.
Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.
Abnormal results mean that toxins produced by C. difficile are seen in the stool and are causing diarrhea.
There are no risks associated with testing for C. difficile toxin.
Several stool samples may be needed to detect the condition. This is especially true if the older EIA for toxin test is used.
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Updated by: Jenifer K. Lehrer, MD, Department of Gastroenterology, Frankford-Torresdale Hospital, Aria Health System, Philadelphia, PA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.
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