From the Guidelines
No, you do not always wait for Clostridioides difficile (C. diff) test results before initiating treatment, especially in cases of suspected severe CDI or fulminant CDI, where empirical therapy should be considered while awaiting test results 1.
Key Considerations
- Empirical therapy for CDI should be avoided unless there is a strong suspicion for CDI 1.
- In cases of suspected severe CDI, antibiotic agent(s) should be discontinued, if possible, and antimicrobial therapy with agents that are less frequently implicated with antibiotic-associated CDI should be used 1.
- Antibiotic therapy is the first choice for CDI, and specific antibiotic therapy guideline recommendations should be based on the severity of the disease, with options including metronidazole, oral or intraluminal vancomycin, and oral fidaxomicin 1.
- Discontinue therapy with the inciting antibiotic agent(s) as soon as possible, as this may influence the risk of CDI recurrence 1.
Clinical Decision Making
- In high-risk patients, early therapeutic intervention before confirmatory test results are available may be necessary to avoid treatment delays 1.
- The decision to initiate treatment before test results are available should be based on the clinical presentation and risk factors for CDI, such as age, chemotherapy, antibiotic agents, and proton pump inhibitors 1.
From the Research
Waiting for C. diff Test Results Before Initiating Treatment
- The decision to wait for C. diff test results before initiating treatment is complex and depends on various factors, including the severity of symptoms and the patient's medical history 2, 3.
- A study published in 2013 found that empiric therapy for CDI was common, but more than half of the empirical treatment was deemed inappropriate because patients did not meet criteria for severe CDI 2.
- Another study published in 2023 highlighted the importance of a multi-step diagnostic approach for CDI, including the use of C. difficile toxin and glutamate dehydrogenase antigen screen (GDH) and nucleic acid amplification testing (NAAT) 3.
- The study also noted that endoscopic evaluation may be required in rare instances when there is a high clinical suspicion of disease with negative testing 3.
Factors Influencing the Decision to Wait for Test Results
- The severity of symptoms is a key factor in determining whether to wait for test results before initiating treatment 2, 4.
- A study published in 2020 found that a prevented C. difficile nucleic acid amplification test was not significantly associated with adverse outcomes compared to a negative test 4.
- Another study published in 2016 found that false negative results can occur with C. difficile testing, and that clinical and analytical sensitivity of C. difficile tests should be considered when deciding which diagnostic assay to use 5.
- A study published in 2014 found that patients who test positive for C. difficile by PCR within 7 days of a negative test are more likely to have a history of CDI than are patients who test negative with repeat PCR 6.
Implications for Clinical Practice
- The studies suggest that a careful evaluation of the patient's symptoms, medical history, and test results is necessary to determine the best course of action 2, 3, 4, 5, 6.
- Clinicians should consider the potential for false negative results and the importance of repeat testing in certain cases 5, 6.
- The use of a multi-step diagnostic approach and consideration of clinical correlates can help improve the accuracy of CDI diagnosis and treatment 3, 4, 5, 6.