Evaluation of Hepatitis B Virus screening strategy in blood donors after the implementation of NAT

Objective To study the possible risk deleting the rounds HBsAg ELISA screening after the nucleic acid testing( NAT) was implemented in donor screening and to evaluate whether the screening strategy one ELISA and NATis better than the strategy two rounds ELISA. Methods 616 unqualified blood samples, which were screened by rounds ELISA with different HBsAg ELISA kits( xinchuang and BIOMERIEUX),were collected. Samples were further tested by NAT,five HBV complementally serological tests and HBsAg Confirmatory test. Donors with kind ELISA + and NAT-but confirmed HBsAg positive were followed and followed samples were tested for the same tests. The false negative risk by deleting ELISA Kit was ana-lyzed. Results Among 616 unqualified samples,31 were ELISA- NAT- but HBsAg Confirmatory test +. Therefore,if specimens were screened by ELISA reagent and NAT,5%( 31 /616) confirmed HBsAg + samples the original round ELISA unqualified samples would not be detected. Thus,16 confirmed HBsAg + cases per 100000 donors would be missed,which was estimated based on the average 0. 32% HBsAg positive rate in donors. On the other hand,three were BIOMERIEUX ELISA- NAT- but HBsAg Confirmatory test +. Therefore,if specimens were screened by BIOMERIEUX ELISA reagent and NAT,0. 5%( 3 /616) confirmed HBsAg + samples the original round ELISA unqualified samples would not be detected. Thus,1. 6 confirmed HBsAg + cases per 100000 donors would be missed,which was also estimated based on the average 0. 32% HBsAg positive rate in donors. Considering the implementation ID can detect additional 121 HBV DNA positive in per 100 000 donors with qualified results by round ELISA( published data),BIOMERIEUX ELISA + NATor Xinchuang ELISA + NATcould detect additional 119. 4 per 100 000 or 105per 100 000 respectively thantwo rounds ELISA. Conclusion As for HBV,the screening strategy one ELISA and NAT can provide a much more HBV safety than the strategy of rounds ELISA. ELISA reagent with better sensitivity and better specificity should be a better choice.