Predonation screening of blood donors with rapid tests: implementation and efficacy of a novel approach to blood safety in resource-poor settings.

BACKGROUND: In sub-Saharan Africa, the percentage of screened blood is limited to approximately 75 percent for human immunodeficiency virus antibodies (anti-HIV), 50 percent for hepatitis B surface antigen, and 19 percent for hepatitis C virus antibodies (anti-HCV), mainly because of costs. STUDY DESIGN AND METHODS: In 2002 to 2003, candidate blood donors were screened before donation for HIV, HCV, and hepatitis B virus (HBV) serologic markers with rapid tests. The efficacy of this screening was assessed by nucleic acid testing (NAT) applied to pools of 10 plasma samples from donated units with a virus specific triplex assay. NAT-reactive pools were resolved by viral genome identification in individual plasma sample. Deferred candidate donors were referred to a donor-care program. RESULTS: A total of 9372 people were screened and 1534 (16.4%) were deferred. No HIV or HCV RNA-containing samples remained undetected by rapid tests unless a human testing error was involved. In contrast, 1.3 and 3.0 percent of HBV DNA-containing blood units were negative with rapid tests but were detected in individual donations with enzyme immunoassay and genomic amplification, respectively. Only half of these units were detectable in pools of 10 samples. One-third of deferred candidate donors attended the donor-care program and were informed and counseled. CONCLUSIONS: Predonation viral screening of blood donors is effective in high endemic areas, and the savings it generates may improve the safety and limit the cost of blood. Communication with deferred donors may contribute to public health. A new screening strategy associating serologic rapid test before donation and NAT on pools of 10 plasma samples after donation is proposed.

The risk of hepatitis B virus infection by transfusion in Kumasi, Ghana.

The risk of hepatitis B virus (HBV) transmission by transfusion in sub-Saharan Africa is considered to be relatively low, and testing of blood donors is often not done or is done relatively poorly. To re-examine this attitude, we identified HBV chronically infected blood donors from a major hospital in Ghana with a range of hepatitis B surface antigen (HBsAg) assays. Test efficacy was estimated using HBV DNA as a gold standard, and the risk of HBV infection in blood recipients was estimated for different testing strategies. Particle agglutination, dipstick, and enzyme immunoassay (EIA) HBsAg screening detected 54%, 71%, and 97% of HBV infectious donors, respectively. The risk of HBV transmission to recipients less than 10 years old ranged between 1:11 and 1:326 with blood unscreened and screened by EIA, respectively. For older recipients, the risk decreased a further 4-fold because of the high frequency of natural exposure to HBV. A total of 98% of HBsAg-confirmed positive samples contained HBV DNA. HBV DNA load was less than 1 x 10(4) IU/mL in 75% of HBsAg-reactive samples, most of them anti-HBe reactive. Approximately 0.5% of HBsAg-negative but anti-HBc-positive samples contained HBV DNA. The use of sensitive HBsAg tests is critical to prevent transfusion transmission of HBV infection to young children in a population with a 15% prevalence of chronic HBV infection in blood donors. However, this will not have much effect on the prevalence of this infection unless other strategies to protect children from infection are also advanced in parallel.