Risk of transfusion associated AIDS by seronegative blood in Thailand: a multicenter report.

Initial measures were taken in 1986 to prevent transfusion-associated AIDS (TAA) in Thailand. The first case of TAA was disclosed in April 1987 five months after which all units of blood at Ramathibodi Hospital and the National Blood Center began to be screened for HIV antibody. The Ministry of Public Health subsequently mandated that all blood be screened from 1989. Despite screening however TAA cases transmitted by presumably seronegative blood have been reported; 9 cases from Chiang Mai and 18 cases from Bangkok since 1985. New seroconverters have also been observed among voluntary blood donors. These phenomena indicate that some people are donating blood during the early stage of HIV infection the window period during which individuals may be infected but their bodies have yet to produce identifiable antibodies against HIV. HIV-P24 antigen ELISA currently seems to be the only available technique for mass screening. The authors assessed the risk of TAA by seronegative blood in Thailand using Coulter HIV p24 Ag assay and the Abbott HIV Ag-1 monoclonal test on blood samples at Ramathibodi Blood Bank and the National Blood Center. They conclude that to obtain safer blood and blood products in Thailand and other populations with a high incidence and prevalence of new HIV infection every unit of blood must be subjected to HIV antigen screening as well as to anti-HIV screening with sensitive assays.