Fecal Specimens Variations: To diagnose CDI, a stool or fecal specimen must be subjected to laboratory testing. Fecal specimens can be challenging because of the complexity involved in the collection, processing, and analysis. Testing fecal matter is more complex than testing serum or blood samples. For CDI testing, it is important that the stool specimen be properly collected and processed. Watery diarrhea stool properly mixed should be collected and submitted for lab analysis. In addition, C difficile toxins are considered heat labile and must be processed in a timely manner. (Typically, the fecal specimen is only considered stable for approximately 4 hours at room temperature, 72 hours refrigerated, and 30 days frozen).
Laboratory Test Limitations: Despite the availability of numerous laboratory methods for the diagnosis of CDI, various tests do have certain limitations. Certain tests may have limitations, such as long turnaround times and technical complexities that can result in delayed treatment of CDIs. Other tests may have low sensitivity and low PPV. To ensure proper treatment and infection control of CDI, testing must be accurate and rapid. More details on laboratory testing for CDI are presented in the following sections.
