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1、OutlineCurrent interventionsHow residual risk is estimatedHow safe is safe? What are the needs?Pathways目前的干预手段如何评估残余风险什么样的安全才是安全的有哪些需要途径Setting the sceneBlood safety is an area of considerable public, regulatory and political concern, even though transfusion appears to be one of the safest therapeut
2、ic measures available.Surveillance, donor selection, testing and hemovigilance, along with the use of quality systems and deferral registries have led to a situation where residual risk for key infections may be lower than one infection in 2 million units transfused.Nevertheless, further measures ar
3、e proposed and are vigorously supported by some thought leaders. Is there a framework for appropriate decision-making, or is it appropriate to continue to seek a zero-risk blood supply? Will the current system of health-care funding support such an approach? 场景设置血液安全是一个非常受公众、行政和政策关注的领域，即使输血似乎是最安全的治疗
4、手段之一。监控、献血者的选择、检测、血液预警以及质量体系和推迟登记的应用，使关键感染的残余风险低于1/200万单位输血。然而，一些思想倡导者仍建议和强烈支持采取进一步的措施。是否有一个适当的决策框架，或者继续寻求一个零风险的血液供应（方案）是否适当？现行的健康保健资金体系未来还能够支持这种做法？ Questions plus testingHBV, HCV, HIV, HTLV, syphilis Testing onlyWNV, T. cruzi, (CMV, bacteria) Questions onlyCJD, vCJD, HAV, malaria, babesia, leishman
5、ia Questions assumed to have impactHHV-8, tropical infections, emergent situations (e.g., SARS) 需要质疑和检测的内容乙型肝炎病毒，丙型肝炎病毒，艾滋病毒，人类嗜T细胞病毒，梅毒螺旋体 只需要检测的内容西尼罗河病毒，克氏锥虫 ， （巨细胞病毒，细菌） 只需要质疑的内容克雅氏病，变种克雅氏病，甲肝，疟疾，巴贝西虫，利什曼原虫 需要质疑假设可产生影响的内容疱疹病毒-8，热带传染病，紧急情况（如非典）Formal approach to hemovigilanceApproval and limited u
6、se of HBV DNA testingChagas testing adopted by majority of blood collectorsBacterial testing by culture, approval for POU test (with very limited claims)WNV testing, with IDT-NAT if necessary最近新增血液预警的标准方法同意和限制使用乙肝病毒DNA检测被多数血液采集者接纳的南美锥虫检测利用培养进行细菌检测，认可使用POU检测（有非常局限的要求）西尼罗病毒检测，必要时对单个样本进行NAT检测Why is the
7、re risk?Failure of selection processAbsence of tests Insensitive testsLaboratory failureMutant or variant organismsWindow period infectionsPeriod in early infection with circulating agent, but prior to test positivity为什么有风险筛选过程失败没有检测不灵敏的检测实验失败病原体突变或变异窗口期感染早期感染期，有循环抗体，但先于测试阳性 Posttransfusion studiesT
8、TV, NIH, FACTSMost infections too infrequent Infectious donationsBusch,Vyas: Culture of seronegative donations for HIV Busch,VyasSimilar issue Back-CalculationHistorical data only通过直接观察来检测风险通过直接观察来检测风险输血后研究新型肝炎病毒 ，美国国立卫生研究院的数据大多数传染很少发生有传染性的献血的研究:艾滋病毒血清学阴性的血液的培养类似的问题追溯只有历史数据01020304019641968197219761
9、98019841988199219962000Year% of Recipients InfectedAll volunteer donorsHBsAgDonor Screening for HIV Risk FactorsAnti-HIVALT/Anti-HBcAnti-HCVHBVHCV3rdgenHBsAgHCV RNA0102030401964196819721976198019841988199219962000Year% of Recipients InfectedAll volunteer donorsHBsAgDonor Screening for HIV Risk Facto
10、rsAnti-HIVALT/Anti-HBcAnti-HCVHBVHCV3rdgenHBsAgHCV RNAAdapted from HJ Alter0102030401964196819721976198019841988199219962000Year% of Recipients InfectedAll volunteer donorsHBsAgDonor Screening for HIV Risk FactorsAnti-HIVALT/Anti-HBcAnti-HCVHBVHCV3rdgenHBsAgHCV RNA01020304019641968197219761980198419
11、88199219962000Year% of Recipients InfectedAll volunteer donorsHBsAgDonor Screening for HIV Risk FactorsAnti-HIVALT/Anti-HBcAnti-HCVHBVHCV3rdgenHBsAgHCV RNA输血相关肝炎风险的减少输血相关肝炎风险的减少Adapted from HJ AlterEstimation of risk from donor datafor known infections with testingWith effective testing, the largest
12、 component of risk is from window period Risk is a function of window period times incidence of new infections Need to define window period Need to define incidenceUpdate by reference to test improvements通过有效的检测，最大的风险因素来自窗口期风险是新感染窗口期的一个作用需要定义窗口期需要定义发病率参考检测技术的改进而更新Measuring incidence ratesNew infecti
13、ons per person, per time Measured among repeat donors With at least 2 donations within a two year study periodNumerator: number of seroconversions Denominator: person-years of observation检测发病率检测发病率每人、每时间段的新发感染在重复献血者中检测两年研究期间内至少献血2次分子：血清转化的数量分母：观察的人-年数Dodd, Notari, Stramer. Transfusion 2002;42:975-97
14、9发病率计算_Dodd, Notari, Stramer. Transfusion 2002;42:975-979Impact of first-time blood donors on window period riskWindow period risk is a function of the length of the window period and the frequency of new infections (incidence) among donors Incidence can be measured among repeat donors by observatio
15、nOther methods are necessary to measure incidence in first-time donors: if the incidence differs, then overall risk estimates must be adjusted.第一次献血者对窗口期风险的影响第一次献血者对窗口期风险的影响窗口期风险是献血者窗口期长度和新发感染频率（发病率）的作用可在重复献血者中通过观察计算发生率必须采用其他方法检测首次献血者中的发病率：如果发病率不同，那么对整体风险的估计必须加以调整。Incidence in first-time donors Use
16、of a less-sensitive (LS) test for HIV (Busch) The proportion of samples positive by the routine test and negative by the LS test can be used to calculate incidence, if the LS window period is known Use of NAT data from routine HCV testing (Dodd) NAT yield and the NAT window period can be used to calculate incidence Both studies found that the incidence (and thus risk) among FT donors was 2.4 X of repeat donors Later data suggests that this approach may be susceptible to bias from test-seekers第一次
