ELISA - Enzyme Linked Immunosorbent Assay. First introduced in 1991, searches the blood sample for certain biochemical sequences which are associated with the presence of antibodies to HCV.   ELISA 1 searched only for the presence of one particular genetically specific to HCV, and was not very reliable. In 1993 it was replaced by ELISA 2, a more comprehensive and reliable test, but still falling short of being accurate. Now ELISA 3 is available, easy to perform, cheap and far more accurate, which makes it usually the initial test nowadays.

RIBA - Recombinant Immunoblot Assay. Was developed as a better alternative to ELISA 1, and went through three generations. It incorporates a search for two different sets of patterns in combination with checking for the presence of a control substance. RIBA 3 is relatively accurate, but being more expensive than ELISA 3 it is used to confirm the later.

Matrix test - uses a technique known as "in vitro enzyme dot blot immunoassay", and seems to be very accurate.