The AmpliVue C. difficile Assay is an in vitro diagnostic test for the direct, qualitative detection of the Clostridium difficile Toxin A gene (tcdA) in unformed stool specimens of patients suspected of having Clostridium difficile-associated disease (CDAD). The assay utilizes helicase-dependent amplification (HDA) for the amplification of a highly conserved fragment of the Toxin A gene sequence and a self-contained disposable amplification detection device that allows for visual evaluation of assay results.
A diluted sample is lysed by simple heat treatment, aliquoted and added to a Reaction Tube containing lyophilized mix of HDA reagents including primers specific for the amplification of a fragment from the conserved region of the C. difficile DNA. Competitive amplification of the process control DNA takes place unless amplification inhibitory substances are present or the sample processing fails. After completion of the HDA reaction, the Reaction Tube is transferred to a Cassette for rapid detection with the test result displayed as test and/or control lines in the window of the Cassette. The dual-labeled probe-amplicon hybrid is then detected by the lateral flow strip within the Cassette. The bottom line captures the test amplicon and the top line captures the control amplicon. The biotin label binds the streptavidin-conjugated color particles for visualization and the molecular test result is shown as colored lines visible to the naked eye.