Confirming a Clostridioides difficile infection (CDI) in a patient presenting with diarrhoea primarily relies on a positive C. difficile toxin test NICE CKS. However, this test result must be interpreted in conjunction with strong clinical suspicion NICE CKS.
It is important to note that C. difficile may be an incidental finding in the stools of people with diarrhoea caused by other factors, and indiscriminate testing increases the likelihood of a false-positive result NICE CKS. Colonisation with C. difficile is common, and individuals who are colonised may be asymptomatic NICE CKS Winslow 2014Ong 2017McDonald 2018.
If a patient has a negative C. difficile toxin test result but there is a strong clinical suspicion of CDI, or if there is doubt, it is advisable to consider seeking specialist advice and potentially retesting NICE CKS. North American guidelines also recommend considering repeat testing in symptomatic individuals with a negative result if there is a high clinical suspicion of CDI NICE CKS McDonald 2018. This approach is consistent with European guidelines and Public Health England advice, which acknowledge that a single negative result can occur NICE CKS Crobach 2016PHE 2018.
Key References
- CKS - Diarrhoea - antibiotic associated
- CG84 - Diarrhoea and vomiting caused by gastroenteritis in under 5s: diagnosis and management
- NG147 - Diverticular disease: diagnosis and management
- CG61 - Irritable bowel syndrome in adults: diagnosis and management
- (Nelson, 2007): Antibiotic treatment for Clostridium difficile-associated diarrhea in adults.
- (Nasiri et al., 2018): Clostridioides (Clostridium) difficile infection in hospitalized patients with antibiotic-associated diarrhea: A systematic review and meta-analysis.