Nanosphere receives FDA clearance for C. difficile test Nanosphere announced the FDA granted 510(k) clearance permitting marketing of its C.difficile test on the automated sample-to-result Verigene System. The C. difficile test expands Nanosphere's infectious disease test capabilities. C. difficile infection is a cause of diarrhea that can lead to colitis, other serious intestinal conditions and death. In less than two hours, the C. difficile test detects the toxin A and B gene sequences of C. difficile and identifies the PCR ribotype 027 strain which is associated with increased severity of disease and used for infection control. Early and accurate diagnosis of C. difficile infections is critical in both the proper treatment of infected patients and subsequent implementation of isolation and containment procedures to prevent further spread of the infection.