The NHS Centre for Evidence based Purchasing (CEP) has published the results of an evaluation of the performance of commercial kits for the detection of C. difficile toxins (http://www.pasa.nhs.uk/pasa/Doc.aspx?Path=%5bMN%5d%5bSP%5d/NHSprocurement/CEP/CEP08054.pdf). The evaluation represents the largest single study of C. difficile toxin detection kits. None of the nine assays tested had a particularly high sensitivity. Also, the poor positive predictive values of the kits, especially in the context of widespread testing, raises doubts about their appropriateness when used as single tests for the laboratory detection of C. difficile toxins.
These Questions and Answers are in response to the results of the CEP evaluation.