Niederhauser Christoph, Mansouri Taleghani Behrouz, Graziani Mauro, Stolz Martin, Tinguely Caroline, Schneider Philippe
Regional Blood Transfusion Service Berne, Bern, Switzerland.
Swiss Med Wkly. 2008 Mar 8;138(9-10):134-41. doi: 10.4414/smw.2008.12001.
The risk of transfusion-transmitted HBV remains significant in Switzerland, where routine screening for hepatitis B virus (HBV) in blood donations relies solely on serological hepatitis B surface antigen (HBsAg) testing. This study was designed to determine the prevalence of anti-hepatitis B core (anti-HBc) and HBV nucleic acid testing (NAT) positive donations in two different Swiss donor populations, to help in deciding whether supplemental testing may bring additional safety to blood products.
In a first population of donors, 18143 consecutive donations were screened initially for HBsAg, anti-HBc (with one EIA assay) and with HBV NAT in minipools of 24 donations. The screening repeatedly reactive anti-HBc donations were then "confirmed" with two supplemental anti-HBc assays, an anti-hepatitis B surface assay (anti-HBs) and with single donation HBV NAT. In a second population of donors, 4186 consecutive donations were screened initially with two different anti-HBc assays in addition to the mandatory HBsAg screening test. The screening repeatedly reactive donations with at least one anti-HBc assay were tested for anti-HBs.
In the first subset of 18143 donations, 17593 (97.0%) were negative for HBsAg, anti-HBc and HBV NAT in minipools. 549 (3.0%) were HBsAg and HBV NAT negative, but repeatedly reactive for anti-HBc. Of these 549 donations, 287 could not be "confirmed" with two additional anti-HBc assays and were negative with an anti-HBs assay, as well as with single donation HBV NAT. Only 211 (1.2% of the total screened donations) were "confirmed" positive with at least one of two supplemental anti-HBc assays. One repeatedly reactive HBsAg donation, from a first-time donor, was confirmed positive for HBsAg and anti-HBc, as well as with single donation HBV NAT. In the second subset of 4186 donations, 4014 (95.9%) were screened negative for HBsAg and for anti-HBc, tested with two independent anti-HBc assays. 172 donations (4.1%) were HBsAg negative but repeatedly reactive with at least one of the two anti-HBc assays. Of these 172 samples, 86 were reactive with the first anti-HBc assay only, 13 were reactive with the second anti-HBc assay only and 73 (1.7% of the total screened donations) were "confirmed" positive with both anti-HBc assays.
The prevalence of anti-HBc "confirmed" positive donations in the two Swiss blood donor populations studied was low (<2%) and we found only one HBV NAT positive (HBsAg positive) donation among more than 18000. Concerning blood product safety, an increase in the deferral rate of less than 2% of anti-HBc positive, potentially infectious donors, would in our opinion make routine anti-HBc testing of blood donations cost-effective. There is however still a need for more specific assays to avoid an unacceptably high deferral rate of "false" positive donors. In contrast, the introduction of HBV NAT in minipools gives minimal benefit due to the inadequate sensitivity of the assay. It remains to evaluate more extensively the value of individual donation NAT, alone or in addition to anti-HBc, as supplemental testing in the context of several Swiss blood donor populations.
在瑞士，输血传播乙肝病毒（HBV）的风险仍然很高，该国献血中乙肝病毒（HBV）的常规筛查仅依靠血清学乙肝表面抗原（HBsAg）检测。本研究旨在确定瑞士两个不同献血者群体中抗乙肝核心抗体（anti-HBc）和HBV核酸检测（NAT）阳性献血的流行率，以帮助决定补充检测是否能为血液制品带来额外的安全性。
在第一组献血者中，对18143份连续献血样本首先进行HBsAg、anti-HBc（采用一种酶免疫测定法）筛查，并在24份献血样本的混合样本中进行HBV NAT检测。然后，对筛查中多次出现反应性的anti-HBc献血样本，用两种补充anti-HBc检测法、一种抗乙肝表面抗体检测法（anti-HBs）以及单份献血样本的HBV NAT检测进行“确认”。在第二组献血者中，除了强制性的HBsAg筛查试验外，对4186份连续献血样本首先用两种不同的anti-HBc检测法进行筛查。对至少一种anti-HBc检测法多次出现反应性的献血样本进行anti-HBs检测。
在18143份献血样本的第一组中，17593份（97.0%）的HBsAg、anti-HBc和混合样本中的HBV NAT检测均为阴性。549份（3.0%）样本HBsAg和HBV NAT检测为阴性，但anti-HBc多次出现反应性。在这549份献血样本中，287份不能通过另外两种anti-HBc检测法“确认”，且anti-HBs检测和单份献血样本的HBV NAT检测均为阴性。只有211份（占总筛查献血样本的1.2%）通过两种补充anti-HBc检测法中的至少一种“确认”为阳性。一份首次献血者的多次出现反应性的HBsAg阳性献血样本，经确认HBsAg、anti-HBc以及单份献血样本的HBV NAT检测均为阳性。在4186份献血样本的第二组中，4014份（95.9%）样本的HBsAg和用两种独立anti-HBc检测法检测的anti-HBc筛查均为阴性。172份（4.1%）样本HBsAg阴性，但至少与两种anti-HBc检测法中的一种多次出现反应性。在这172份样本中，86份仅与第一种anti-HBc检测法反应，13份仅与第二种anti-HBc检测法反应，73份（占总筛查献血样本的1.7%）通过两种anti-HBc检测法均“确认”为阳性。
在所研究的两个瑞士献血者群体中，anti-HBc“确认”为阳性的献血样本流行率较低（<2%），并且在超过18000份样本中我们仅发现一份HBV NAT阳性（HBsAg阳性）献血样本。关于血液制品安全，我们认为将anti-HBc阳性、潜在感染性献血者的延期率提高不到2%，会使献血的常规anti-HBc检测具有成本效益。然而，仍需要更特异的检测方法以避免“假”阳性献血者的延期率高得不可接受。相比之下，由于检测灵敏度不足，在混合样本中采用HBV NAT带来的益处极小。仍有待更广泛地评估单份献血样本NAT单独使用或与anti-HBc联合使用作为瑞士几个献血者群体补充检测的价值。
