A versatile portfolio of diagnostic tests is essential for the containment of the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) pandemic. Besides nucleic acid-based test systems and point-of-care (POCT) antigen (Ag) tests, quantitative, laboratory-based nucleocapsid Ag tests for SARS-CoV-2 have recently been launched. Here, we evaluated four commercial Ag tests on automated platforms and one POCT to detect SARS-CoV-2. We evaluated PCR-positive (n = 107) and PCR-negative (n = 303) respiratory swabs from asymptomatic and symptomatic patients at the end of the second pandemic wave in Germany (February–March 2021) as well as clinical isolates EU1 (B.1.117), variant of concern (VOC) Alpha (B.1.1.7) or Beta (B.1.351), which had been expanded in a biosafety level 3 laboratory. The specificities of automated SARS-CoV-2 Ag tests ranged between 97.0 and 99.7% (Lumipulse G SARS-CoV-2 Ag (Fujirebio): 97.03%, Elecsys SARS-CoV-2 Ag (Roche Diagnostics): 97.69%; LIAISON^® SARS-CoV-2 Ag (Diasorin) and SARS-CoV-2 Ag ELISA (Euroimmun): 99.67%). In this study cohort of hospitalized patients, the clinical sensitivities of tests were low, ranging from 17.76 to 52.34%, and analytical sensitivities ranged from 420,000 to 25,000,000 Geq/ml. In comparison, the detection limit of the Roche Rapid Ag Test (RAT) was 9,300,000 Geq/ml, detecting 23.58% of respiratory samples. Receiver-operating-characteristics (ROCs) and Youden’s index analyses were performed to further characterize the assays’ overall performance and determine optimal assay cutoffs for sensitivity and specificity. VOCs carrying up to four amino acid mutations in nucleocapsid were detected by all five assays with characteristics comparable to non-VOCs. In summary, automated, quantitative SARS-CoV-2 Ag tests show variable performance and are not necessarily superior to a standard POCT. The efficacy of any alternative testing strategies to complement nucleic acid-based assays must be carefully evaluated by independent laboratories prior to widespread implementation.

多种诊断测试组合对于遏制严重急性呼吸系统综合症冠状病毒 2 型 (SARS-CoV-2) 大流行至关重要。除了基于核酸的检测系统和即时 (POCT) 抗原 (Ag) 检测外，最近还启动了针对 SARS-CoV-2 的基于实验室的定量核衣壳抗原检测。在这里，我们评估了自动化平台上的四项商业 Ag 测试和一项检测 SARS-CoV-2 的 POCT。我们评估了 PCR 阳性 ( n  = 107) 和 PCR 阴性 ( n = 303) 在德国第二次大流行结束时（2021 年 2 月至 3 月）以及临床分离株 EU1 (B.1.117)、关注变异体 (VOC) Alpha (B.1.1) 的无症状和有症状患者的呼吸道拭子。 7) 或 Beta (B.1.351)，已在生物安全 3 级实验室中扩展。自动化 SARS-CoV-2 Ag 测试的特异性介于 97.0 和 99.7% 之间（Lumipulse G SARS-CoV-2 Ag (Fujirebio)：97.03%，Elecsys SARS-CoV-2 Ag（罗氏诊断）：97.69%；LIAISON ^®SARS-CoV-2 Ag（Diasorin）和 SARS-CoV-2 Ag ELISA（Euroimmun）：99.67%）。在该住院患者研究队列中，检测的临床敏感性较低，范围为 17.76% 至 52.34%，分析敏感性范围为 420,000 至 25,000,000 Geq/ml。相比之下，罗氏快速抗原检测 (RAT) 的检测限为 9,300,000 Geq/ml，检测了 23.58% 的呼吸道样本。进行了接受者操作特征 (ROC) 和约登指数分析，以进一步表征检测的整体性能，并确定灵敏度和特异性的最佳检测临界值。通过所有五种测定法检测到核衣壳中携带多达四种氨基酸突变的挥发性有机化合物，其特征与非挥发性有机化合物相当。总之，自动化，定量 SARS-CoV-2 Ag 测试显示出可变性能，不一定优于标准 POCT。在广泛实施之前，必须由独立实验室仔细评估任何替代测试策略以补充基于核酸的测定的功效。