In India, nearly 12 million are estimated to be infected by Hepatitis C. Most infections remain unknown, undiagnosed and untreated. Hepatitis C virus is transmitted through blood to blood contact like transfusion of contaminated blood, blood products, use of unsterilised needles and syringes. Mandatory screening of donated blood for Hepatitis C virus was introduced as late as 2002 under the National Blood Policy. Blood banks now screen for Hepatitis C along with Hepatitis B, HIV, Syphillis and Malaria. But many had already been infected before the policy came into being. For most people, early detection is purely by chance when they donate blood or undergo medical tests for jobs abroad. Sutapa Deb reports.