Hepatitis B virus testing by minipool nucleic acid testing: does it improve blood safety?

Area of Science:

• Blood Transfusion Safety
• Virology
• Public Health

Background:

• Hepatitis B virus (HBV) DNA-positive yield was previously reported following nucleic acid testing (NAT) implementation using minipools of 16 (MP16).
• Updated figures on HBV yield, evaluation of all HBV tests, and residual risk calculations before and after MP-NAT introduction were needed.
• Estimation of residual risks with potential improvements in HBV screening for US blood donations was also considered.

Purpose of the Study:

• To update HBV DNA-positive yield figures since the implementation of MP-NAT.
• To evaluate the current value of all HBV screening tests.
• To calculate and estimate residual risks for US blood donations, considering potential future screening improvements.

Main Methods:

• Screening of approximately 12.8 million donations using US-required serologic HBV tests and MP-NAT.
• Confirmation of MP-NAT-reactive and -nonreactive donations using individual-donation polymerase chain reaction (ID-PCR).
• Calculation of incidence and residual risk using the hepatitis B surface antigen (HBsAg)-yield method and the incidence-window-period model.

Main Results:

• A total of 1368 HBV confirmed positives were observed, with 941 detected by MP-NAT.
• Five seronegative NAT-yield donations (1:2.6 million) and 25 HBsAg-yield donations were identified.
• MP-NAT reduced the window period by 8.8 days, decreasing residual risk to 1:765,000–1:1,006,000, comparable to HIV and HCV.

Conclusions:

• HBV MP-NAT and decreased HBV incidence have significantly reduced residual transfusion risks in the US.
• Current residual risks are comparable to those for human immunodeficiency virus (HIV) and hepatitis C virus (HCV).
• The necessity of all three HBV markers for blood donation screening warrants re-evaluation, with potential for more sensitive ID-NAT methods.