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“AbC-19快速免疫分析法”检测新冠病毒感染的准确性较低
作者:小柯机器人 发布时间:2020/11/15 0:21:05

英国公共卫生部David H Wyllie团队研究了“AbC-19快速检测法”检测此前SARS-CoV-2感染的关键工作者的准确性。2020年11月11日,该研究发表在《英国医学杂志》上。

为了评估AbC-19快速侧流免疫分析法检测既往感染SARS-CoV-2患者的准确性,研究组进行了一项检测准确性研究。

2020年6月,研究组在英格兰招募了2847名关键工作者(卫生保健人员、消防和救援人员以及警察),其中268名此前有聚合酶链反应(PCR)阳性结果,2579名先前感染状况未知,1995名在大流行前曾献过血。主要结局指标为使用已知的阴性(大流行前)样品和已知的阳性(PCR确认)样品作为参考标准来评估AbC-19检测方法的敏感性和特异性。

检测结果带通常很弱,3名训练有素的实验室工作人员对结果呈阴性或阳性的判定存在3.9%的不一致。使用三人判断均一致的数据,对于已知的阳性和阴性样品,敏感性为92.5%,特异性为97.9%。

使用免疫检测参考标准,在PCR确诊病例中,敏感性为94.2%,而在其他有抗体的人群中,敏感性为84.7%。抗体浓度越高,AbC-19检测的敏感性越高,这是因为经PCR确诊的人往往患有更严重的疾病,而只有62%(218/354)的血清阳性患者有症状。

如果有100万关键工作者接受了AbC-19的检测,而此前人群的实际感染率为10%,那么预计将有84700个真阳性和18900个假阳性结果。阳性结果正确的可能性为81.7%。

结果表明,由于“光谱偏倚”,在未选择的人群中,AbC-19检测方法的敏感性低于经PCR确诊的SARS-CoV-2病例。

附:英文原文

Title: Accuracy of UK Rapid Test Consortium (UK-RTC) “AbC-19 Rapid Test” for detection of previous SARS-CoV-2 infection in key workers: test accuracy study

Author: Ranya Mulchandani, Hayley E Jones, Sian Taylor-Phillips, Justin Shute, Keith Perry, Shabnam Jamarani, Tim Brooks, Andre Charlett, Matthew Hickman, Isabel Oliver, Stephen Kaptoge, John Danesh, Emanuele Di Angelantonio, Anthony E Ades, David H Wyllie

Issue&Volume: 2020/11/11

Abstract:

Objective To assess the accuracy of the AbC-19 Rapid Test lateral flow immunoassay for the detection of previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

Design Test accuracy study.

Setting Laboratory based evaluation.

Participants 2847 key workers (healthcare staff, fire and rescue officers, and police officers) in England in June 2020 (268 with a previous polymerase chain reaction (PCR) positive result (median 63 days previously), 2579 with unknown previous infection status); and 1995 pre-pandemic blood donors.

Main outcome measures AbC-19 sensitivity and specificity, estimated using known negative (pre-pandemic) and known positive (PCR confirmed) samples as reference standards and secondly using the Roche Elecsys anti-nucleoprotein assay, a highly sensitive laboratory immunoassay, as a reference standard in samples from key workers.

Results Test result bands were often weak, with positive/negative discordance by three trained laboratory staff for 3.9% of devices. Using consensus readings, for known positive and negative samples sensitivity was 92.5% (95% confidence interval 88.8% to 95.1%) and specificity was 97.9% (97.2% to 98.4%). Using an immunoassay reference standard, sensitivity was 94.2% (90.7% to 96.5%) among PCR confirmed cases but 84.7% (80.6% to 88.1%) among other people with antibodies. This is consistent with AbC-19 being more sensitive when antibody concentrations are higher, as people with PCR confirmation tended to have more severe disease whereas only 62% (218/354) of seropositive participants had had symptoms. If 1 million key workers were tested with AbC-19 and 10% had actually been previously infected, 84700 true positive and 18900 false positive results would be projected. The probability that a positive result was correct would be 81.7% (76.8% to 85.8%).

Conclusions AbC-19 sensitivity was lower among unselected populations than among PCR confirmed cases of SARS-CoV-2, highlighting the scope for overestimation of assay performance in studies involving only PCR confirmed cases, owing to “spectrum bias.” Assuming that 10% of the tested population have had SARS-CoV-2 infection, around one in five key workers testing positive with AbC-19 would be false positives.

DOI: 10.1136/bmj.m4262

Source: https://www.bmj.com/content/371/bmj.m4262

期刊信息

BMJ-British Medical Journal:《英国医学杂志》,创刊于1840年。隶属于BMJ出版集团,最新IF:27.604
官方网址:http://www.bmj.com/
投稿链接:https://mc.manuscriptcentral.com/bmj