Published online Mar 21, 2014. doi: 10.3748/wjg.v20.i11.2948
Revised: December 23, 2013
Accepted: February 20, 2014
Published online: March 21, 2014
Processing time: 171 Days and 17.3 Hours
Screening tests for blood donations are based upon sensitivity, cost-effectiveness and their suitability for high-throughput testing. Enzyme immunoassay (EIAs) for hepatitis C virus (HCV) antibodies were the initial screening tests introduced. The ”first generation“ antibody EIAs detected seroconversion after unduly long infectious window period. Improved HCV antibody assays still had an infectious window period around 66 d. HCV core antigen EIAs shortened the window period considerably, but high costs did not lead to widespread acceptance. A fourth-generation HCV antigen and antibody assay (combination EIA) is more convenient as two infectious markers of HCV are detected in the same assay. Molecular testing for HCV-RNA utilizing nucleic acid amplification technology (NAT) is the most sensitive assay and shortens the window period to only 4 d. Implementation of NAT in many developed countries around the world has resulted in dramatic reductions in transfusion transmissible HCV and relative risk is now < 1 per million donations. However, HCV serology still continues to be retained as some donations are serology positive but NAT negative. In resource constrained countries HCV screening is highly variable, depending upon infrastructure, trained manpower and financial resource. Rapid tests which do not require instrumentation and are simple to perform are used in many small and remotely located blood centres. The sensitivity as compared to EIAs is less and wherever feasible HCV antibody EIAs are most frequently used screening assays. Efforts have been made to implement combined antigen-antibody assays and even NAT in some of these countries.
Core tip: This is a review article on development and current status of screening tests for hepatitis C virus (HCV) infection in blood donors. The sensitivity of HCV antibody assays, HCV core antigen assays and combination assays are discussed. Effect of nucleic acid amplification technology implementation of blood safety is highlighted. Future prospects for developed countries and resource constrained countries are presented.