Abstract: Objective To study on the re-entry strategy of nucleic acid testing reactive blood donors based on HBV infection confirmation. Methods Multiple highly sensitive in-house nucleic acid testing (NAT) methods and routine blood NAT screening platforms were combined with serological testing and blood donor follow-up to confirm HBV infection to identify infection status in NAT-yield blood donors. The efficiency of different NAT methods, HBV markers and marker combinations were compared in detection and confirmation of HBV infections. Results From November 2010 to February 2021, 511 in 876 NAT-yield blood donors were confirmed to be infected with HBV (451 OBIs, 27 acute early HBV infections, 33 infected with HBV but infection status unidentified, 30 without infection, and 335 HBV infection unconfirmed). The detection rate of HBV DNA in HBV-infected plasma yielded by minipool NAT (MP-NAT) was 96.6% when individual NAT (ID-NAT) was used, which was significantly higher than those of HBV DNA reactive samples (HBV DNA R) and non-discriminatory reactive samples (NDR) yielded by ID-NAT (76.4% and 55.7%, respectively) (P<0.05). The detection rate (65.2%) of NDR samples under retesting mode 2 (ID×5+ Discrimination×2) was higher than that (39.2%) under retesting mode 1 (ID×2+Discrimination ×1) (P<0.05). The detection rate of HBV DNA R samples under the two retesting modes had no significant difference (P>0.05), but was clearly higher than that of NDR samples (P<0.05). Reviewing the previous NAT data of OBI blood donors, 46% had experienced multiple NAT without detection. And HBV DNA was not detected in 59.1% of OBI blood donors during follow-up. The proportion of anti-HBc+ in OBIs was 90.2%, while that of anti-HBc+ alone was 49.2%, which was much higher than that in HBV infection unconfirmed group (P<0.05). The proportions of HBeAg, anti-HBe and anti-HBc IgM in OBI were very low, similar with that of infection unconfirmed groups (P>0.05). Conclusion HBV infections were confirmed in nearly 60% of NAT-yield blood donors. HBV DNA confirmation technology with higher sensitivity is needed to improve the confirmation rate of HBV infection, which ensured the safety of re-entry blood donors. Anti-HBc was the most important serological marker in excluding the risk of OBI and assessment of NAT-yield donor's re-entry.

Key words: Nucleic acid testing, Blood donor re-entry, Hepatitis B virus infection, Confirmation, Follow up