ObjectivesTo:calculate the number needed to screen (NNS) and community effectiveness of combination treatment (interferon-α plus ribavirin) compared with its efficacy of 28 to 45%;compare the cost of opportunistic hepatitis C virus (HCV) screening and combined treatment to prevent 1 high risk patient developing cirrhosis with the cost of liver transplantation; andput a cash value on how much purchasing authorities should bid in a commissioning round for new HCV treatments.DesignA financial option appraisal of liver transplantation versus opportunistic HCV screening and treatment;a financial/commissioning model from a purchaser’s perspective using the latest national and international standards/guidelines and audit reports.Setting and participantsWest Kent Health Authority (963 000 residents and 9 primary care groups). All patients at high risk of HCV presenting to health services in 1998/1999 who had an anti-HCV test.ResultsUsing current National Institute of Clinical Excellence (NICE) guidance (combined treatment for moderate to severe liver changes), about 113 479 high risk persons need to be screened and medically treated, costing about 50 947 pounds sterling (£) to prevent 1 patient developing cirrhosis in 10 to 20 years. The community effectiveness therefore is 0.00088%. The net present value (NPV) of HCV screening and combined treatment is −£32 471 to −£25 407 to prevent 1 patient developing cirrhosis compared with liver transplantation; and the marginal cost to fund current volumes is £54 000. In contrast, if current international standards were used (which advocates combined treatment for mild, moderate and severe liver changes), the NNS is 118 to prevent 1 high risk patient developing cirrhosis; the community effectiveness is 0.847%; the NPV is −£6479 to £584; and the variable cost to fund current volumes is £796 850.ConclusionThe community effectiveness of combined treatment, at best (i.e. using the international model), is 33 to 53 times less than its efficacy; HCV screening and drug treatment is more expensive than liver transplantation. Furthermore, the international model is a far more technically efficient pathway for delivering HCV care than that recommended by NICE guidance.