US Patent 8993341 Removal of PCR inhibitors

Provided herein is technology relating to processing and preparing samples and particularly, but not exclusively, to methods, systems, and kits for removing assay inhibitors, e.g, compounds that inhibit polymerase chain reaction, from samples comprising nucleic acids. In particular, the technology is directed toward treating crude sample preparations, such as supernatants from homogenized stool samples, with insoluble polyvinylpyrrolidone (PVP) to form PVP-assay inhibitor complexes, and spin filtration to separate the PVP-assay inhibitor complexes from the crude sample preparations to produce clarified samples that exhibit reduced assay inhibition.