The United States is at a “transition point” when it comes to diagnosing Clostridium difficile (C. diff), experts say. Complicating efforts to document the increasing burden of severe C. diff is the current migration of laboratories to more sensitive diagnostic tests for detection of the infection as well as the multitude of diagnostic testing strategies. Two recent studies highlight both the transition of testing approaches, as well as some of the remaining limitations on testing. Experts say either multistep approaches using polymerase chain reaction (PCR) for the toxin gene(s) or single-step PCR on liquid stool samples have the highest sensitivity and specific- ity. Yet, testing is unable to differentiate asymptomatic colonization and symptomatic infection, leading experts to remind clinicians that diagnostic testing for C. diff infection should be performed only in symptomatic patients. According to new data released by the U.S. Centers for Disease Control and Prevention (CDC) in a study published Feb. 26 in the New England Journal of Medicine (NEJM), C. diff caused almost half a million infections in the United States in 2011. A convenience sample of 37 clinical laboratories across the Emerging Infections Program (EIP) sites submitted all C. diff–positive stool specimens from cases with full […]