Despite the use of highly sensitive serologic tests for screening blood donations for antibodies to HIV-1, HTLV-I/II, HCV and HBV in US blood centers, the delay between the onset of infection and the antibody response creates a """"""""window"""""""" period during which the blood may be infectious but seronegative. As a result, a low risk of virus transmission due to contaminated blood products still exists. During PHASEI of this grant, we have developed a Multiplex RT-PCR based capture assay which permits the simultaneous direct detection of HTLV-I/II, HIV-1, HCV and HBV in a single assay. In the course of PHASE II, we propose to further refine this Multiplex RT-PCR assay, and to develop a kit format useful for routine screening of blood products in a clinical lab setting. The assay will be validated on a number of well characterized performance and seroconversion panels for all five viruses and on large numbers (>1,000) of blood samples from normal blood donors. This test will provide a highly sensitive, cost-effective direct measure of infectious virus in blood and help further reduce the antibody-negative """"""""window"""""""" period between infectivity and detection.
