A material which is used to verify the performance of an assay intended to be used for the qualitative and/or quantitative detection of nucleic acid, including specific gene markers, from Clostridium difficile bacteria [e.g., genes conferring antimicrobial resistance (e.g., gyrA gene), virulence (e.g., ribotype 027), and genes encoding toxin A and/or B] in a clinical specimen and/or culture isolate.