Choosing Wisely®: C. difficile Infection Testing
Clostridium difficile infection continues to be a concern as the most common healthcare-associated infection, causing almost half a million gastrointestinal illnesses in the United States in 2011.1
Toxin enzyme immunoassays (EIAs) to diagnose C. difficile infection were relied on in the past, but lack adequate sensitivity to rule out disease. At Cleveland Clinic, EIA has been replaced with an FDA-approved nucleic acid amplification test (NAAT) targeting the C. difficile toxin B gene.
Because a positive test for C. difficile toxin may represent colonization rather than infection, it is important to limit testing to patients with a reasonable probability of having disease. The Centers for Disease Control and Prevention and several professional societies have issued recommendations for utilization of C. difficile testing to avoid detection of colonized patients:
- Limit orders for difficile testing to patients with clinically significant diarrhea (three or more loose stools within 24 hours).2 Patients with ileus that may be associated with C. difficile infection are an exception to this testing criteria.
- Don’t perform difficile testing unless patients have signs or symptoms of infection. Tests can be falsely positive leading to over diagnosis and overtreatment.3,4
- Don’t obtain a test of cure since nonviable DNA or a colonized state may be detected; therapeutic response should be based on clinical signs and symptoms.5
- Don’t use antibiotics in patients with recent difficile without convincing evidence of need. Antibiotics pose a high risk of C. difficile recurrence.3
- Routine testing in children under 3 years of age should be avoided, since there is a high rate of asymptomatic carriage in this age group and difficile infection is rare.6
Dr. Sandra Richter, microbiology section head, reminds clinicians, “Don’t order a C. difficile test for patients with other likely causes of diarrhea (eg, recent laxative, lactulose, or enteral feeding), insignificant diarrhea (fewer than three loose stools per day unless ileus is present), or no history of antimicrobial therapy. To avoid detection of colonized patients, our laboratory only performs C. difficile testing on stools that conform to the shape of the container.”
- Lessa FC, Yi M, Bamberg WM, Beldavs ZG, et al. 2015. Burden of Clostridium difficile infection in the United States. New England Journal of Medicine372;9,825-834.
- Centers for Disease Control and Prevention. http://www.cdc.gov/HAI/organisms/cdiff/Cdiff_clinicians.html
- Society for Healthcare Epidemiology of America
- Infectious Diseases Society of America
- AMDA – The Society for Post-Acute and Long-Term Care Medicine
- Choosing Wisely: an initiative of the American Board of Internal Medicine. http://www.choosingwisely.org
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