上海地区无偿献血者乙肝病毒核酸检测分析

目的了解无偿献血者乙肝病毒核酸筛查(NAT)阳性人群特点,为血液安全策略提供参考。方法无偿献血者血液经Murex和科华HBsAg ELISA试剂检测,结果为阴性的血液使用cobas TaqScreen MPX试剂进行HBV DNA,HCV RNA,HIV RNA 3项联合核酸检测。对于MPX反应性标本,使用COBAS AmpliPrep/TaqMan进行核酸鉴别试验,同时使用罗氏ECL电化学发光检测系统进行乙肝补充血清学试验。结果 2011年11月1日～2012年1月31日3个月共有献血者86 375人(次),其中有63 351人(次)为初次献血者,HBsAg反应性为1.04%,23 024人(次)为重复献血者,HBsAg反应性为0.46%,两者差异有统计学意义(χ2=63.63,P0.05)。84 990份HBsAg、抗-HCV、抗-HIV1/2阴性血液进行MPX核酸检测,共发现52例(0.060%)HBV DNA阳性,均为低拷贝,含量为(20～200)IU/ml间,其中32例(0.051%)来自初次献血者,20例(0.087%)来自重复献血者,两者比例差异无统计学意义(χ2=3.65,P0.05),没有发现HCV RNA与HIV RNA阳性。结论重复献血者HBsAg反应性比率低于初次献血者;HBsAg阴性献血者HBV DNA阳性率为0.060%,重复献血者HBV DNA阳性率与初次献血者比较,两者差异无统计学意义;开展HBV核酸检测能够进一步保障血液安全。     

江苏省HBV反应性献血者归队评估模式及其可行性探讨

目的:评估HBV反应性献血者归队风险,探讨HBV归队策略的可行性。方法:对江苏地区既往因HBs Ag+或HBV DNA+被屏蔽的无偿献血人群,屏蔽期6个月后重新抽血,进行常规ELISA(HBs Ag、抗HCV、HIV Ab/Ag、抗TP ELISA)筛查和3次NAT混样检测。对于ELISA和核酸无反应性的标本,再采用电化学发光法(ECLIA)进行HBV血清学标志物(HBs Ag、HBs Ab、HBe Ag、HBe Ab、HBc Ab)检测。结合HBV血清学标志物检测结果与献血者乙肝疫苗注射史,设定4种HBV血清学标志物合格模式,综合评估献血者是否符合归队要求。另外,比较常规筛查与ECLIA法两种检测模式在HBV感染的检出率及HBs Ag+和HBV DNA+献血者的归队合格率上的差异。结果:2016年10月至2019年8月共有737名HBV初筛反应性献血者提出归队申请,其中既往因HBs Ag+或HBV DNA+被屏蔽的献血者分别为667例和70例。737名献血者重新抽血并接受检测,其中通过血清学标志物检测对HBV的检出率最高,占比43.15%(318/737),HBs Ag ELISA法...     

免疫筛查阴性献血者血样病毒核酸检测的研究

目的了解二次酶联免疫筛查献血者血样漏检的原因。方法将二次酶联免疫筛查阴性的献血者血样在加样仪上实现血液样本汇集,用全自动核酸提取仪提取样本核酸,以核酸扩增检测仪做HBV、HCV和HIV自动扩增检测。对HBsAg阴性、HBVDNA阳性献血者用核酸筛查试剂定量检测HBV,并每隔2周对其跟踪采血,做HBV两对半免疫检测和HBsAgV3的确认试验。结果16320份二次酶联免疫筛查阴性的合格献血者血样中,8份HBVDNA阳性(漏检率0.49‰),未发现HCV和HIV1RNA阳性。8份HBVDNA阳性献血者乙肝两对半免疫检测HBsAg、HBsAb和HBeAg均为阴性,HBcAb均为阳性,3份HBeAb为阳性。6例HBsAg阴性HBVDNA阳性献血者血样的病毒滴度在(76～1490)copies/ml,2例病毒滴度过低,未定量检测到病毒。跟踪6名HBVDNA阳性献血者,1例18周时HBsAg确认试验阳性,其余5例仍为阴性。结论现行的二次酶联免疫技术的血液筛查存在HBV漏检,原因可能是隐匿性乙型肝炎病毒感染。应重视血液筛查工作中HBV的漏检及输血传播,并在现有的血液筛查模式中或增加HBcAb检测,或增加病毒核酸筛查。     

Hepatitis B virus (HBV) DNA screening of blood donations in minipools with the COBAS AmpliScreen HBV test

BACKGROUND: The risk of hepatitis B virus (HBV) transmission by blood transfusion (estimated at 1 in 63,000-1 in 205,000 units in the United States) exceeds that of hepatitis C virus (HCV) or human immunodeficiency virus (HIV). Reduction of window-period HBV transmissions through detection of HBV DNA-positive units by minipool nucleic acid testing (MP NAT) would be expected to decrease this risk. STUDY DESIGN AND METHODS: A large multicenter study of the COBAS AmpliScreen HBV test (Roche Molecular Systems) was conducted on minipools of 24 blood donation specimens. The yield of HBV DNA-positive, hepatitis B surface antigen (HBsAg)-negative window-period donations was determined relative to current and newly licensed HBsAg assays. Donors with selected HBV DNA, HBsAg, and anti-hepatitis B core antigen (HBc) results were further evaluated. RESULTS: The detection rate of window-period units was 1 in 352,451 (95% confidence interval, 1 in 2,941,176-1 in 97,561). Assay specificity was high (99.9964%). HBV DNA was detected in 84 percent of HBsAg-positive, anti-HBc-positive donations by MP NAT and in 94 percent when individual-donation (ID) NAT was added. HBV DNA was detected in 0.03 percent of HBsAg-negative, anti-HBc-positive donations by MP NAT and in 0.41 percent when ID NAT was added. CONCLUSIONS: Implementation of HBV MP NAT will provide an increment in safety relative to HBV serologic screening, similar to that for HCV and in excess of that for HIV. Our data indicate that the implementation of HBV MP NAT would likely interdict 39 HBV window-period units and prevent 56 cases of transfusion-transmitted HBV infection annually. The current data indicate that HBV MP NAT should not lead to discontinuation of anti-HBc testing but that discontinuation of HBsAg testing with retention of anti-HBc testing may be possible.     

青岛地区无偿献血者乙型肝炎病毒感染血清学和病毒特征分析

目的 分析青岛地区无偿献血者乙型肝炎病毒感染的血清学及病毒学特征.方法 采用常规的血清学试验和核酸扩增技术对本地区315 520份无偿献血者标本进行联合筛查,对HBsAg-/HBV DNA+标本进行高精度病毒载量检测和补充乙肝5项检测,采用PCR直接测序法获得标本中HBsAg编码基因即S基因序列,分析病毒基因型别及氨基...     

单检及16份混样检测模式对献血者核酸检测效果的比较研究

目的 探讨单份及16份混合标本2种检测模式对献血者血液病毒核酸检测(nucleic acid test,NAT)效果的影响.方法 2009年2至6月顺序留取北京无偿献血者标本,用诺华Procleix ULTRIO Assay进行单份(ID)或16份混合标本(P16)乙型肝炎病毒(HBV)、丙型肝炎病毒(HCV)和人类免疫缺陷病毒-1( HIV-1)三项联合核酸检测.单份NAT反应性同时HBsAg、抗-HCV或抗-HIV血清学不合格的标本,血清学合格的单份NAT反应性经双孔NAT复检阳性的标本,以及混合NAT反应性/拆分NAT为阳性的标本,进一步用诺华Procleix HBV、HCV和HIV-1鉴别试剂进行鉴别试验.血清学合格、HBV NAT单独阳性标本进一步用Roche HBV定量实验加以验证和进行病毒含量测定、血清学分析、并进行稀释以模拟是否能被P16-NAT检出.阳性检出率进行四格表连续校正的x2检验.结果 (1)在7613份单份NAT (ID-NAT)标本中,检出NAT阳性26份,ID-NAT阳性率0.34％(26/7613);(2)在16 064份共1004份P16混合标本NAT(P16-NAT)中,检出NAT阳性27份,P16-NAT阳性率为0.17％ (27/16 064);(3)在血清学合格标本中,单份检测的NAT单独阳性检出率为0.12％ (9/7438),高于16份混样检测的NAT单独阳性检出率0.01％ (2/15 750)(x2=11.880,P＜0.05).9份ID-NAT及2份P16-NAT单独阳性标本经鉴别均为HBV NAT阳性,未检出 HCV NAT单独阳性或HIV NAT单独阳性;(4)9份ID-NAT HBV单独阳性血样模拟P16-NAT,仅有2份可被检出;(5)对8份ID-NAT及2份P16-NAT单独阳性标本进行Roche HBV定量测定,均可确证其核酸检测结果,但病毒含量很低.其中2份HBV病毒含量为472 IU/ml及15 IU/ml,6份含量＜12 IU/ml,另2份原倍不能定量经10倍浓缩处理后测得含量为＜ 12 IU/ml和14.3 IU/ml;(6)11份HBV NAT单独阳性标本中,3份(27.3％)为潜在的窗口期感染,其余8份(72.7％)抗-HBc阳性或抗-HBe阳性,但抗-HBc-IgM均为阴性,为隐匿性感染;(7) P16-NAT初检呈反应性需要进行拆分试验的混合样本比率为2.49％ (25/1004),其中由血清学合格标本所致初检反应性的混合样本比率为0.20％ (2/1004).结论 ID-NAT单独阳性检出率高于P16-NAT单独阳性检出率.为避免低病毒含量HBV的漏检,应选用灵敏度高的核酸检测试剂,并尽量采用小标本量混合检测,甚至采用单份检测方式.     

献血者筛查方法与风险模型的初探

目的探讨现行免疫学检测乙型肝炎5项、艾滋病、梅毒等8项感染指标方法的安全性,并探索适合我国国情的输血传播病毒性疾病HBV、HCV、HIV核酸扩增(NAT)检测方法及可行性。方法采用酶标法对我院库存血和血浆共计4 726份,进行乙型肝炎5项、丙型肝炎、艾滋病及梅毒检测。结果HBsAg、抗-HCV、抗-HIV和梅毒阳性数(阳性率)分别40(0.85%)、6(0.12%)、0(0)、1(0.02%)。抗-HBc阳性1390份,阳性率29.41%;单抗-HBc阳性146份,阳性率3.09%。结论采用酶标法检测抗-HCV阳性率低于HCV核酸检测法;核酸检测可早期发现“窗口期”献血者病毒感染指标,宜在献血者中开展此项检测,并需建立献血者的风险模型。     

Evaluation of a multiplex human immunodeficiency virus-1, hepatitis C virus, and hepatitis B virus nucleic acid testing assay to detect viremic blood donors in northern Thailand

BACKGROUND: Screening of blood donors with nucleic acid testing (NAT) for human immunodeficiency virus (HIV) and hepatitis C virus (HCV) has been implemented recently in the United States. There are limited data, however, on the additional NAT yield of donors in developing countries in Asia where the prevalence of infection is higher. In addition, data on hepatitis B virus (HBV) NAT in high prevalence areas are minimal. STUDY DESIGN AND METHODS: A total of 5083 whole-blood donors at the Chiang Mai University Hospital, Thailand, blood bank were evaluated with a commercially available NAT assay (Procleix Ultrio, Gen-Probe, Inc.) to screen individual donations. RESULTS: No NAT yield cases were found for HIV-1 or HCV. There were 17 samples with discrepant HBV DNA NAT and hepatitis B surface antigen (HBsAg) tests, however. Seven of these were HBV DNA NAT-positive, HBsAg-negative; of these 7, 1 was NAT-positive at baseline, but negative on follow-up, and considered a false-positive, 1 had an acute infection, and 5 had chronic prevalent HBV infections, for a NAT yield of 6 in 4798 HBsAg negative donors (1:800). In addition there were 10 NAT-negative, HBsAg-positive serum samples. All were anti-hepatitis B core antigen immunoglobulin G-positive; on testing with a more sensitive NAT target capture assay, 5 were positive (1.8-20.6 IU/mL) and 5 were negative. CONCLUSION: Multiplex NAT screening of individual-donor serum samples in Northern Thailand detected approximately 1 per 800 HBV NAT-positive, HBsAg-negative donors. The especially high prevalence of HBV infection in Thailand and other Asian countries suggests that HBV NAT screening of donors will be more cost-effective than in other areas.     

Transfusion-transmitted HBV infection in an endemic area: the necessity of more sensitive screening for HBV carriers

BACKGROUND: By NAT, HBV DNA is occasionally detectable in blood donors with past HBV infection but negative for HBsAg. Whether or not these donors can cause transfusion-transmitted HBV infections is uncertain. STUDY DESIGN AND METHODS: To determine whether or not donors with past HBV infection but negative for HbsAg can cause HBV transfusion-transmitted infections, recipients followed for blood transfusion in a university medical center in Taiwan were studied. HBV DNA and serologic markers were tested in donors and recipients. RESULTS: Of 1,038 enrolled recipients, 910 completed the 6-month post-transfusion follow-up visit. Of these, only 39 patients (4.3%) tested negative on the pretransfusion sample for HBsAg, anti-HBs, anti-HBc, and HBV DNA by PCR. These 39 HBV-naive recipients had been transfused with blood from 147 donations for which stored samples were available for HBV DNA testing by PCR; 11 of these HBsAg-negative samples tested positive for HBV DNA and anti-HBc. Two of the 11 patients who received the HBV-DNA-positive donations (18%) became positive for HBV DNA, and one seroconverted to anti-HBc and finally to anti-HBs, with a mild transient elevation of serum ALT activities. Based on the one confirmed case of HBV transmission, a projection was made that approximately 200 post-transfusion HBV infections could occur in one million units of transfused blood in Taiwan. CONCLUSIONS: In HBV-endemic areas like Taiwan, where blood donors are screened for HBsAg only, the risk of transfusion-transmitted HBV appears to be substantial. Implementation of NAT for blood screening in these settings warrants consideration.     

核酸扩增技术在献血者血液HBV DNA、HCV RNA及HIV-1 RNA筛查中的应用研究

目的探讨在我国无偿献血者的血液筛查中引进核酸扩增技术(NAT)的必要性,了解献血者血清学病毒标志物检测阴性、NAT检测阳性的感染状况。方法应用Roche PCR、PCR-微流芯片、实时荧光PCR方法对深圳市131 174人(次)血清学检测病毒标志物阴性的献血者进行HBV DNA、HCV RNA和HIV-1 RNA检测,对NAT阳性献血者追踪检测并做定量分析。结果HBV DNA阳性22例,阳性率为1/5 962,其中15例为抗-HBc阳性,阳性率为1/8 745;HCV RNA阳性1例,阳性率1/131 174;HIV-1 RNA未检出阳性。对14名HBV DNA阳性者的追踪发现,8人发生了血清转换现象。结论采用高灵敏度的NAT筛查献血者血液中的HBV和HCV,有助于提高输血及血液安全。     

江苏地区献血者隐匿性HBV感染情况调查

目的调查无偿献血人群中隐匿性乙型肝炎病毒的携带率,病毒载量与血清学标志物检出的关系。方法对无偿献血者血液进行ELISA检测后,再行HBV、HCV、HIV核酸检测(NAT)。ELISA阴性、NAT阳性样品再进行HBVDNA、HCV RNA、HIV RNA定量检测及HBsAg、HBsAb、HBeAg、HBeAb、HBcAb化学发光法检测。结果共检测51 248份献血者血液样品,检出41例隐匿性HBV感染者,其携带率为0.80‰;血浆HBV病毒载量均小于66IU/ml;HBcAb阳性者23例,占56.1%;HBcAb伴HBsAb阳性者14例,占34.1%;HBsAb阳性4例,占9.7%。HBsAb或伴HBcAb阳性组与单一HBcAb阳性组相比,HBV DNA含量的差异无统计学意义(P<0.05)。结论江苏地区无偿献血者中隐匿性HBV感染率约为0.80‰;其HBV病毒载量均较低,且血清学标志物的检出模式与病毒载量无相关性。     

Occult hepatitis B virus infection in Thai blood donors

BACKGROUND: An evaluation by the National Blood Center, the Thai Red Cross Society, of two commercial multiplex nucleic acid tests (NATs; the Chiron PROCLEIX ULTRIO test and the Roche Cobas TaqScreen MPX test) for screening Thai blood donors for hepatitis B virus (HBV), hepatitis C virus, and human immunodeficiency virus Type 1 identified 175 HBV NAT–reactive/hepatitis B surface antigen (HBsAg)‐negative donors. The classification of the HBV infection of these donors was confirmed by follow‐up testing. STUDY DESIGN AND METHODS: Index samples were tested for HBV serologic markers and HBV viral loads were determined. Donors were followed for up to 13 months and samples were tested with both NAT assays and for all HBV serological markers. RESULTS: Of 175 HBV NAT–yield donors, 72 (41%) were followed. Based on the follow‐up results, the majority of donors who were followed had an occult HBV infection (66.7%), followed by donors with a primary, acute infection (26.4%). The majority of donors in this latter group (20.8%) were in the window period. Three donors (4.2%), who were anti‐HBs positive, had a reinfection or breakthrough infection. CONCLUSION: The majority of donors detected during routine screening, who were HBsAg negative and NAT reactive, had an occult HBV infection, thus validating the decision to introduce NAT for blood donations in Thailand.     

NAT positivity in seronegative voluntary blood donors from western India

Background and objectives

Prevalence and composition of Hepatitis B, Hepatitis C and HIV-1, NAT positive but seronegative voluntary blood donors from western part of India is yet to be documented.

无偿献血者血液ELISA、NAT法检测与ALT结果分析

目的探讨无偿献血者NAT法检测和ALT筛检在血液安全中的作用。方法对无偿献血者的ELISA法、NAT法和ALT法检测结果进行分析,并对ALT异常者进行追溯性调查。结果在10 062例无偿献血者中,共检出360例ALT异常（淘汰率3.6%）,其中有3例伴HBsAg和HBV DNA阳性,3例伴抗-HCV和HCV RNA阳性;检出10例HBV DNA阳性而ALT、HBsAg均正常者;未检出ALT异常伴HBV DNA或HCV RNA阳性,且ELISA法检测结果正常者。对354例单一ALT异常者的追溯性调查发现,其中35例反复献血,表现为连续或间断ALT异常。结论NAT法检测可以降低ELISA法的漏检风险,而ALT对降低输血传染病残留风险的作用仍值得探讨。     

无偿献血者血液感染HBV/HCV/HIV的两种检测方案比较研究

目的 比较酶联免疫法（ELISA）对无偿献血者血液HBsAg/抗HCV/HIV/Ag/Ab阳性检出率及核酸分析技术（NAT）对HBV/HCV/HIV阳性检出率,为优化血液安全检测方案提供依据.方法 采用A方案（用两种不同生产厂家的ELISA试剂盒检测HBsAg/抗HCV/HIV/Ag/Ab,无反应性样本再进行NAT HBV/HCV/HIV检测）对2011年1月-2013年7月采集的198 783例无偿献血者血样进行检测;采用B方案（用1种ELISA试剂盒检测HBsAg/抗HCV/HIV/Ag/Ab,无反应性样本再进行NAT HBV/HCV/HIV检测）对2013年8月-12月采集的34 577例无偿献血者血样进行检测,运用统计学方法分析A,B两种检测方案的阳性检出率.结果 A方案的ELISA阳性检出率（1.32％）高于B方案的ELISA阳性检出率（0.76％）（χ^2=75.291,P＜0.05）;A方案的总阳性检出率（1.45％）高于B方案的总阳性检出率（0.92％）（χ^2=61.016,P＜0.05）;A方案ELISA检测的阳性检出率（1.32％）高于B方案总体阳性检出率（0.92％）（χ^2=38.986,P＜0.05）.结论 采用A方案对无偿献血者血液感染HBV/HCV/HIV进行检测的阳性检出率较高,能够较好地保证血液安全,但会增加检测成本和工作量.     

HBsAg阴性献血者人群HBV感染的检测和输血残余风险分析

目的 了解献血人群乙型肝炎病毒(HBV)感染状况和血液经酶免疫法(EIA)筛查乙型肝炎病毒表面抗原(HBsAg)后经血传播HBV感染的残余风险.方法 采用国产和进口两种EIA试剂对献血者血液进行HBsAg筛查,罗氏诊断COBAS Ampliscreens NAT血筛系统检测EIA检测合格标本中HBV DNA,对HBV DNA阳性标本进行半套式PCR检测,并对PCR扩增产物进行测序和病毒基因亚型分析.结果 共筛查1998～2008年的献血者232 305例,发现HBsAg阳性2 999例,阳性率为1.3%;对2002～2007年EIA检测合格的113 639例献血者血液标本进行NAT检测,检测出13份HBV DNA阳性、HBsAg阴性的献血者血液,HBV残余风险高达1.1/10 000.结论 EIA筛查后血液安全性有了很好的保障,经血传播HBV残余风险依然处于较高的水平,NAT应用对提高血液安全,降低输血传播HBV残余风险意义重大.     

不同核酸检测方法对献血者隐匿性乙肝病毒感染的研究

目的了解无偿献血者中隐匿性乙肝病毒感染情况,并比较不同核酸检测方法对隐匿性乙肝病毒感染检测能力的差异。方法分别采用nested-PCR和Procleix Ultrio全自动核酸检测系统对无偿献血者血浆标本进行HBV核酸检测,对核酸阳性标本进行HBV DNA序列分析。结果在总计9 209例次标本的检测中,共有9 159例为HBsAg(-);HBsAg(-)标本中nested-PCR方法检出18例HBV DNA阳性(0.19%,18/9 159),而Procleix Ultrio检出7例(0.076%,7/9 159),两者间差异有统计学意义(P<0.05);测序结果显示隐匿性HBV感染者中C基因型所占的比例(64.7%,11/17)明显高于HBsAg阳性的HBV感染者(23.1%,6/23,P<0.01)。结论闽南地区无偿献血者中存在较高比例的隐匿性乙肝病毒感染;不同核酸检测方法对献血者隐匿性乙肝病毒感染的检测能力存在差异。     

乙型肝炎两对半和HBVDNA定量检测的临床应用

目的探讨乙型肝炎病毒（HBV）免疫标志物（HBV-M）与HBVDNA之间的相互关系，为临床诊断、治疗乙型肝炎提供有价值的判断标准。方法用时间分辨荧光免疫法（TRFIA）定量检测HBV-M，并与荧光定量聚合酶链反应检测HBVDNA相比较。结果105例乙型肝炎表面抗原（HBsAg）、乙型肝炎e抗体（抗-HBe）、乙型肝炎核心抗体（抗—HBc）均为阳性；85例HBsAg、HBeAg、抗-HBc均为阳性；34例乙型肝炎病毒抗体（抗-HBs）、抗-HBe、抗HBc阳性组中HBVDNA的检出率分别为65．7％、95．5％和11．7％。以HBsAg含量为100ng／mL作为HBV复制的诊断限，其特异性和敏感性分别是70．0％和84．0％。结论TRFIA定量检测HBV-M灵敏度高、特异性强、操作简便，无放射性污染，是一种较好的HBV-M测定方法，在实验室不具备HBVDNA定量测定的条件下，选择TRFIA进行乙型肝炎两对半定量检测也是一种较好的方法。     

Lack of correlation between HBsAg and HBV DNA levels in blood donors who test positive for HBsAg and anti-HBc: implications for future HBV screening policy

BACKGROUND: Studies showing a significant correlation between hepatitis B surface antigen (HBsAg) and hepatitis B virus (HBV) deoxyribonucleic acid (DNA) levels have focused on the HBV seroconversion window period. STUDY DESIGN AND METHODS: HBsAg levels relative to HBV DNA results in 200 HBsAg-positive, anti-hepatitis B core antigen (HBc)-reactive blood donations were analyzed using quantitative polymerase chain reaction (PCR) (detection limit 400 copies/mL), two research PCR assays with increasing sensitivities (65 copies/mL and 1.3 copies/mL, respectively), and a quantitative HBsAg assay; HBsAg and HBV DNA levels were correlated with HBV serologic profiles; and the potential for replacing HBsAg screening with nucleic acid testing (NAT) was analyzed. RESULTS: Serologic profiles for over 90 percent of the donor samples were consistent with chronic HBV infection. Correlation between HBsAg and HBV DNA concentrations was weak (correlation coefficient = 0.33). Thirty-six percent (72/200) of donor samples had DNA levels under 400 copies per mL. Retesting of the 72 samples by more sensitive PCR assays showed that 60 out of 200 (30%) were positive by PCR with sensitivity of 65 copies per mL, whereas 6 out of 200 (3%) required PCR sensitivity of 1.3 copies per mL for positivity. Three percent (6/200) were negative by all three NAT assays. CONCLUSIONS: HBV DNA levels in HBsAg-positive, anti-HBc-reactive blood donations can be extremely low. About 6 percent of donations would be negative by current minipool HBV NAT methods. About 3 percent of donations would remain undetected by sensitive single-donor NAT. These results indicate caution in any consideration of dropping HBsAg screening.     

Comparative sensitivity of HBV NATs and HBsAg assays for detection of acute HBV infection

BACKGROUND: A study was designed to estimate relative analytic sensitivity and window-period (WP) closure and to project incremental yield of newer HBsAg tests, pooled-sample NAT, and single-sample NAT, compared to currently licensed HBsAg tests. STUDY DESIGN AND METHODS: HBV DNA and HBsAg test results for 23 HBV seroconversion (SC) panels were first analyzed to construct a model of primary HBV viremia. One-hundred representative samples were then selected from 10 panels and coded with 28 analytical controls. All 128 samples were tested by seven HBsAg tests and by four pooled-sample and three single-sample NAT assay formats. Results were analyzed to obtain differential times to HBV detection and combined with HBV incidence rates to project comparative yields. RESULTS: HBV doubling time during the ramp-up phase was estimated at 2.56 days. HBsAg concentrations at cutoff for new tests ranged from 0.07 to 0.12 ng per mL, compared with 0.13 to 0.62 ng per mL for licensed tests. Estimated viral load at cutoff ranged from 102 to 267 IU per mL for new tests and from 363 to 1069 IU per mL for licensed tests. HBsAg tests detected 31 to 63 percent of early ramp-up phase samples in the 100-member seroconversion panel study, while pooled-sample NAT detected 55 to 71 percent and single-sample NAT, 82 to 99 percent. Compared with currently licensed HBsAg assays, newer HBsAg assays would reduce the WP by 2 to 9 days; pooled-sample NAT would reduce the WP by 9 to 11 days; and single-sample NAT would reduce the WP by 25 to 36 days. CONCLUSION: Newer HBsAg tests would be expected to detect an additional 15 to 21 infected units per 107 donations, compared to licensed HBsAg tests. Sensitivity, WP closure, and yield projections for newer HBsAg assays and pooled-sample NAT are comparable. Single-sample NAT would increase yield by 13 to 15 units per 107 donations over pooled-sample NAT and newer HBsAg assays and by 35 to 50 units per 107 donations over currently licensed HBsAg assays.