Residual Risk of Hepatitis-B-Infected Blood Donations: Estimation Methods and Perspectives

Table 1

Principal methods for the calculation of HBV residual risk based on serological markers HBsAg and/or anti-HBc.

Method (reference)	Probability of HBV infection	Incidence type	Probability of window-period donation	WP (days)
Standalone HBsAg [63]	∑𝑠1/∑pyrs	Rate	0.7 (∑𝑠1/Mdn (IDI𝑠1)) + 0.05	59
Müller-Breitkreutz model [64]	∑𝑠1/𝑛rd	Cumulative	WP/Mdn(IDI𝑠1)	59
HBsAg yield [65]	∑𝑠2/𝑛rd	Cumulative	WP/Mdn(IDI𝑠2)	44
HBsAg and anti-HBc yield [66]	∑𝑠3/∑pyrs	Rate	1 if anti-HBc positive,; 0.7 (∑𝑠1/∑IDI𝑠1) + 0.05 if HBsAg+ and anti-HBc negative; ≈1	44
Modified standalone HBsAg [44]	∑𝑠1/∑pyrs	Rate	WP/Mean (IDI𝑠1)	59

𝑠1: number of HBsAg-seroconverting repeat donors (independent of anti-HBc result).
𝑠2: number of HBsAg-seroconverting repeat donors who were anti-HBc negative on all testing occasions.
𝑠3: number of HBsAg- or anti-HBc-seroconverting repeat donors (in the last 365 days).
𝑛_rd: number of repeat donors.
WP: duration of immunologic window period.
IDI: interdonation interval (between last seronegative and first seropositive donation).
Pyrs: person-years at risk for HBV infection (∑IDI for all repeat donors−0.5∑ IDI_𝑠1).
Mdn: median.