• Rationale and Comments

    Repeat testing using the nucleic acid amplification test (within seven days) for C. difficile is not recommended when the symptoms represent a single episode of diarrheal illness. Studies have shown that repeat testing using the nucleic acid amplification test within a seven-day period yields only a 2% diagnostic yield. Exceptions should only be made in the setting of an institutional epidemic or when C. difficile infection is highly suspected with no alternative diagnosis, but for which the initial test is negative and symptoms persist or worsen.

    Sponsoring Organizations

    • American Society for Microbiology


    • IDSA guideline


    • Gastroenterologic
    • Infectious disease


    • McDonald LC, Gerding DN, Johnson S, et al. Clinical practice guidelines for Clostridium difficile infection in adults and children: 2017 update by the Infectious Diseases Society of America (IDSA) and Society for Healthcare Epidemiology of America (SHEA). Clin Infect Dis. 2018;66(7):987-994.
    • Luo RF, Banaei N. Is repeat PCR needed for diagnosis of Clostridium difficile infection? J Clin Microbiol. 2010;48(10):3738-3741.
    • Surawicz CM, Brandt LJ, Binion DG, et al. Guidelines for diagnosis, treatment, and prevention of Clostridium difficile infections. Am J Gastroenterol. 2013;108(4):478-498.