hepatitis reactive qualitative detected hbsag rna hcv ribonucleic surface acid virus hepatitis positive hcv immunodeficiency rna known hiv antigen ribonucleic hepatitis seronegative antibody antigen tested rna rt pcr hcv reverse hcv rna hepatitis positive antibody negative ribonucleic acid pcr virus hcv hepatitis hbv virus positive rna surface antigen antibody acid