Department of Laboratory Medicine, Iris Hospitals South, Brussels, Belgium.
Department of Laboratory Medicine, Iris Hospitals South, Brussels, Belgium; Department of Pharmacy, Namur Research Institute for Life Sciences, University of Namur, Belgium; Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium.
J Clin Virol. 2020 Aug;129:104472. doi: 10.1016/j.jcv.2020.104472. Epub 2020 May 30.
The COVID-19 Ag (Antigen) Respi-Strip assay is a new immunochromatographic diagnostic tool recently available for antigenic diagnosis of SARS-CoV-2. The proposed sensitivity is not higher than 60 %, but its high specificity allows both quick decisions for the management of patients and confirmation by molecular diagnosis for only negative tests. However, from the first tests performed, we suspected that the sensitivity observed with routine use was much lower than that announced by the manufacturer.
Over a period of one month, we compared the negative results obtained with the COVID-19 Ag Respi-Strip kit with those obtained from qRT-PCR performed in a laboratory qualified for the molecular diagnosis of SARS-CoV-2. All samples tested were naso-pharyngeal smears from UTM-RT medium.
Of 774 patients tested, 714 negative samples were sent for confirmation, and 159 were found to be positive by qRT-PCR. The median positive percentage agreement was 23.9 % (95 % CI: 14.2 %-38.2 %). The Cohen's kappa score was 0.35.
Using this immunochromatographic assay as a triage test did not significantly reduce the number of samples outsourced for COVID-19 confirmation by qRT-PCR. In addition, even if the turn-around time is short, the assay is completely manual, which is not suitable for large volumes of routine samples. The sensitivity of this rapid test is poor, and improvements are needed to enhance its performance.
COVID-19 Ag（抗原）Respi-Strip 检测法是一种新的免疫层析诊断工具，最近可用于 SARS-CoV-2 的抗原诊断。提出的灵敏度不高于 60%，但其高特异性允许快速做出决策来管理患者，并仅对阴性检测进行分子诊断确认。然而，从最初的测试中，我们怀疑常规使用中观察到的灵敏度远低于制造商宣布的灵敏度。
在一个月的时间里，我们将 COVID-19 Ag Respi-Strip 试剂盒获得的阴性结果与在经过 SARS-CoV-2 分子诊断资格认证的实验室进行的 qRT-PCR 获得的结果进行了比较。所有测试的样本均为来自 UTM-RT 介质的鼻咽拭子。
在 774 名接受测试的患者中，有 714 个阴性样本被送确认，其中 159 个样本经 qRT-PCR 检测为阳性。阳性百分比的中位数符合率为 23.9%（95%CI：14.2%-38.2%）。Cohen's kappa 评分是 0.35。
将这种免疫层析检测法作为一种分诊测试并不能显著减少需要进行 qRT-PCR 确认的 COVID-19 样本数量。此外，即使周转时间很短，该检测法完全是手动操作，不适合常规样本的大量检测。这种快速检测的灵敏度较差，需要改进以提高其性能。
