American Red Cross, Holland Laboratory, Rockville, Maryland.
American Red Cross, Scientific Affairs, Gaithersburg, Maryland.
In the United States, blood donor testing for hepatitis B surface antigen (HBsAg) was initiated in the early 1970s. More recently, testing for antibody to hepatitis B core antigen (anti-HBc) and hepatitis B virus (HBV) DNA have been added. The incidence of hepatitis B has been declining. This study reviews the current status of testing and questions the need for continuation of HBsAg testing.
STUDY DESIGN AND METHODS:
From July 2011 to June 2015, a total of 22.4 million donations were serologically tested for HBsAg and anti-HBc and for HBV-DNA by nucleic acid testing (NAT). All reactive results were evaluated and a subset of donations that were either potential NAT yield (seronegative) or serologically positive but nonreactive by HBV NAT in minipools (MPs) of 16 were further evaluated by individual donation (ID)-NAT. Samples with detectable HBV DNA were defined as actively infected and considered potentially infectious.
Routine testing plus supplemental ID-NAT identified 2035 samples representing active infection including 1965 with anti-HBc, 1602 with HBsAg, and 1453 with HBV DNA by MP-NAT, for respective rates per hundred-thousand donations of 9.10, 8.78, 7.16, and 6.50, continuing the downward trend previously observed. There were 29 HBV DNA-yield samples (1:771,389), 35 HBsAg-yield samples (anti-HBc nonreactive), and 404 with occult hepatitis B infection. There were six samples with HBsAg and HBV DNA detectable only by ID-NAT in the absence of anti-HBc; additional testing was consistent with extremely low or negligible levels of DNA.
Point estimates of HBV infection rates among blood donors continue to decline, as do those for incidence and residual risk. Elimination of HBsAg screening would have negligible impact, with a risk less than 1 per 4 million donations.