Test of Cure for C. difficile Should NOT Be Performed
A test of cure after completing C. difficile treatment is not recommended and should not be performed. 1, 2
Why Testing After Treatment Is Not Indicated
More than 60% of successfully treated patients continue to shed C. difficile spores asymptomatically for up to 6 weeks after clinical resolution. 1, 2 This means:
- Laboratory testing cannot distinguish between asymptomatic colonization and active infection 1, 2
- A positive test after treatment does not indicate treatment failure or need for additional therapy 2
- The Infectious Diseases Society of America explicitly recommends against routine post-treatment testing 2
How to Assess Treatment Success
Diagnosis of cure should be based solely on clinical criteria—specifically, resolution of diarrhea—not laboratory testing. 2 Treatment success is defined as:
- Resolution of diarrhea (fewer than 3 unformed stools in 24 hours) 2
- Symptoms typically resolve within hours to 4-5 days on average after starting appropriate treatment 2
- The patient remains well with no requirement for further C. difficile therapy 3, 4
When to Consider Repeat Testing
Testing should only be performed if diarrhea recurs after initial symptom resolution. 2, 5 Specific scenarios include:
- New onset of diarrhea (≥3 unformed stools in 24 hours) after documented resolution 2
- Clear changes to clinical presentation, such as change in character of diarrhea or new supporting clinical evidence 2
- Do not repeat testing within 7 days of initial testing during the same diarrheal episode, as diagnostic yield is only approximately 2% 2, 5
Common Pitfalls to Avoid
Up to 35% of patients experience recurrent symptoms due to transient functional bowel disorder in the first two weeks following C. difficile resolution. 1, 2 This can lead to:
- Unnecessary repeat testing and false-positive results 2
- Misdiagnosis of post-infectious irritable bowel syndrome as recurrent infection 1, 2, 5
- Inappropriate retreatment of asymptomatic colonization 1
Multiple repeat testing carries high risk of generating false-positive results, particularly with tests of suboptimal specificity. 2
Special Populations
For patients treated with fecal microbiota transplantation (FMT), routine testing for C. difficile after FMT is not recommended. 2 Testing is only appropriate in cases of persistent symptoms or suspected relapse. 2
Key Guideline Recommendations
The Society for Healthcare Epidemiology of America and Infectious Diseases Society of America advise: