Busch M P, Watanabe K K, Smith J W, Hermansen S W, Thomson R A
Division of Research and Scientific Services, Blood Centers of the Pacific-Irwin Center, San Francisco, CA 94118, USA.
Transfusion. 2000 May;40(5):585-9. doi: 10.1046/j.1537-2995.2000.40050585.x.
The contribution of testing errors to the risk of virus transmission by transfusion depends on the rate of false-negative testing errors and the prevalence of infected seropositive donations. Although the false-negative testing error rate has been estimated at 0.1 to 1 percent on the basis of proficiency studies, it has not previously been measured in routine donor screening.
A 1991 to 1995 database containing 5,153,153 donations from 1.5 x 10(6) donors (including autologous donors) was searched to identify donors who tested seropositive for HIV, HCV, HTLV-I or II and who attempted subsequent donations. The false-negative rate in routinely screened follow-up donations was determined, and false-negative cases were investigated to identify the cause.
Subsequent donations (n = 2015) by 1224 donors with confirmed-positive results were identified. Eleven (0.5%) of these donations did not react in EIA. Ten of the 11 false-negative cases were attributable to borderline-reactive donations. On subsequent donations, there were borderline-nonreactive results on HTLV-I (2 cases), first-generation HCV (5 cases), and second-generation HCV (3 cases) EIAs. The final case was strongly reactive for HCV in a second-generation EIA on two donations (signal-to-cutoff [S:C] ratio >3.5), followed by a baseline nonreactive result on a third donation (S:C = 0.05).
False-negative testing results occur infrequently during routine infectious-disease donor screening. Although most false-negative results occurred with borderline-reactive HTLV-II samples and/or early-generation HCV EIAs, frank technical errors (e.g., sample mixup or failure to add sample to EIA well) also occur at a low rate (0.05%; 95% CI, 0-1.5%). Process enhancements designed to reduce errors (e.g., enhanced automation of data management and testing systems and process controls for EIAs) are warranted to detect and prevent false-negative results.
检测误差对输血传播病毒风险的影响取决于假阴性检测误差率以及感染血清学阳性献血的流行率。尽管根据能力验证研究估计假阴性检测误差率为0.1%至1%，但此前尚未在常规献血者筛查中进行测量。
检索1991年至1995年的数据库，该数据库包含来自150万名献血者（包括自体献血者）的5153153次献血记录，以识别HIV、HCV、HTLV-I或II血清学检测呈阳性且随后再次献血的献血者。确定常规筛查的后续献血中的假阴性率，并对假阴性病例进行调查以确定原因。
识别出1224名检测结果确诊为阳性的献血者的后续献血（n = 2015）。其中11次（0.5%）献血在酶免疫测定（EIA）中无反应。11例假阴性病例中有10例归因于临界反应性献血。在后续献血中，HTLV-I（2例）、第一代HCV（5例）和第二代HCV（3例）EIA出现临界非反应性结果。最后一例在两次献血的第二代EIA中HCV呈强反应性（信号与临界值[S:C]比值>3.5），而第三次献血时基线结果为非反应性（S:C = 0.05）。
在常规传染病献血者筛查中，假阴性检测结果很少出现。尽管大多数假阴性结果出现在临界反应性HTLV-II样本和/或早期一代HCV EIA中，但明显的技术错误（如样本混淆或未将样本加入EIA孔中）也以低发生率出现（0.05%；95%置信区间，0 - 1.5%）。为减少误差而设计的流程改进措施（如增强数据管理和检测系统的自动化以及EIA的过程控制）对于检测和预防假阴性结果是必要的。
