The present disclosure relates to a method for detecting a core polypeptide of a hepatitis C virus (HCV) in a sample from a subject involving (a) contacting said sample with a base and with a surfactant having a cationic detergent, and (b) detecting a core polypeptide of the HCV in the sample. The present invention further relates to a method for pre-processing a sample from a subject for detection of HCV, involving contacting the sample with a base and with a surfactant having a cationic detergent; and to a pre-processing reagent for detecting HCV in a sample, having a base and a surfactant including a cationic detergent, wherein the surfactant also has a nonionic detergent. Moreover, the present disclosure further relates to kits, uses, and devices related to the methods disclosed.