Abstract: Objective The aim of this study was to explore the screening of occult hepatitis B viral infection (OBI) in unpaid blood donors with low-level viremia (LLV) by serum HBV DNA precise detection technology. Methods 11352 unpaid blood samples with negative serum hepatitis B surface antigen (HBsAg) were collected between February 2017 and December 2021. Serum hepatitis B e antigen (HBeAg), anti-hepatitis B e antibody (HBeAb), anti-hepatitis B core antibody (HBcAb) and serum anti-hepatitis B surface antibody (HBsAb) were qualitatively or quantitatively detected by CL-2000i automatic chemiluminescence immunoassay. Serum biochemical parameters were detected by AU5800 automatic biochemical analyzer. Serum HBV DNA loads were assayed by ABI ViiA7 fluorescence quantitative PCR amplifier by means of high-sensitivity PCR assay. All individuals with positive seru HBV DNA by high-sensitivity PCR assay were checked-up by Cobas AmpliPrep/Cobas TaqMan automatic nucleic acid quantitative detection system. Results The high-sensitivity PCR detection found 67 blood donors (0.59%) were serum HBV DNA positive with LLV from the 11352 blood samples, which were completely coincided with the gold method of automatic nucleic acid quantitative detection system, with the sensitivity and specificity of 100.0% (67/67) and 100.0% (67/67), respectively; there was no statistical significance as respect to serum HBV DNA loads detected by gold standard method and high-sensitivity PCR [(110.7±20.2) IU/ml vs. (108.2±19.6) IU/ml, P>0.05]; the high-sensitivity PCR detection found serum HBV DNA loads were 100-200 IU/ml in 41 cases (61.2%), 20-100 IU/ml in 15 cases (22.4%) and <20 IU/ml in 11 cases (16.4%); serum HBV DNA loads in 5 blood samples with serum HBsAb/ HBeAb/ HBcAb positive were (162.4±18.3) IU/ml, significantly higher than [(82.3±14.1)IU/ml, P<0.05] in 9 blood samples with serum HBcAb positive or [(136.9±15.7)IU/ml, P<0.05] in 16 blood samples with serum HBeAb/ HBcAb positive or [(99.3±15.5)IU/ml, P<0.05] in 32 blood samples with serum HBsAb/ HBcAb positive or [(71.5±12.9)IU/ml, P<0.05] in 3 blood samples with serum HBsAb positive or [55.0 IU/ml和56.1 IU/ml, respectively] in 2 blood samples with all serum HBV markers negative. Conclusion The screening of serum HBV DNA by high-sensitivity PCR in unpaid blood donors could reveal OBI with LLV, which might be more safe in clinical blood use.

Key words: Occult hepatitis B viral infection, HBV DNA precise detection technology, Unpaid blood donors, Low-level viremia, Screening