Skip navigation

Stool C. difficile toxin

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.

How the Test is Performed

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.

How to Prepare for the Test

There are many ways to collect the samples.

  • You can catch the stool on plastic wrap that is loosely placed over the toilet bowl and held in place by the toilet seat. Then you put the sample in a clean container.
  • A test kit is available that supplies a special toilet tissue that you use to collect the sample. After collecting the sample, you put it in a container.

Do not mix urine, water, or toilet tissue with the sample.

For children wearing diapers:

  • Line the diaper with plastic wrap.
  • Position the plastic wrap so that it will prevent urine and stool from mixing. This will provide a better sample.

Why the Test is Performed

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.

Normal Results

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.

What Abnormal Results Mean

Abnormal results mean that toxins produced by C. difficile are seen in the stool and are causing diarrhea.

Risks

There are no risks associated with testing for C. difficile toxin.

Considerations

Several stool samples may be needed to detect the condition. This is especially true if the older EIA for toxin test is used.

References

DuPont HL. Approach to the patient with suspected enteric infection. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 291. 

Semrad CE. Approach to the patient with diarrhea and malabsorption. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap142.

Giannella RA. Infectious enteritis and proctocolitis and bacterial food poisoning. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger & Fordtran’s Gastrointestinal and Liver Disease. 9th ed. Philadelphia, PA: Saunders Elsevier; 2010:chap 107. 

Croft AC, Woods GL. Specimen collection and handling for diagnosis of infectious diseases. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 63.

Salwen MJ, Siddiqi HA, Gress FG, Bowne WB. Laboratory diagnosis of gastrointestinal and pancreatic disorders. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 22.

Update Date: 5/15/2014

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.

A.D.A.M Quality Logo

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 1997-2014, A.D.A.M., Inc. Duplication for commercial use must be authorized in writing by ADAM Health Solutions.

A.D.A.M Logo