Lau Chin Shern, Phua Soon Kieng, Hoo See Ping, Jiang Boran, Aw Tar-Choon
Department of Laboratory Medicine, Changi General Hospital, Singapore 529889, Singapore.
Department of Microbiology, Changi General Hospital, Singapore 529889, Singapore.
Vaccines (Basel). 2022 Jan 27;10(2):198. doi: 10.3390/vaccines10020198.
SARS-CoV-2 antigen tests can complement and substitute for RT-PCR tests. Centralized laboratory automated SARS-CoV-2 antigen tests that can be scaled to process a large number COVID-19 cases simultaneously are now available. We have evaluated the new Roche Elecsys SARS-CoV-2 antigen electro-chemiluminescent immunoassay.
The Roche SARS-CoV-2 antigen assay is a double-antibody sandwich electro-chemiluminescent immunoassay, which reports a cut-off index (COI) (COI ≥ 1.0 considered positive). We assessed assay precision and linearity, and confirmed the reactivity limit. We determined the assay sensitivity and specificity with a verification group (289 controls and 61 RT-PCR positive COVID-19 cases). Assay performance was also validated against the consecutive samples we received (7657 controls and 17 cases) for SARS-CoV-2 antigen testing from June to October 2021.
The assay had a within-run precision CV of 3.0% at COI 0.68, and a CV of 1.5% at COI 3.49. Between-run precision was 3.0% at COI 0.68 and 1.8% at COI 3.49. The assay was linear from COI 0.65 to 7.84. All 35 C ± 20% test results performed over 7 days were positive/negative, respectively. In the verification group, overall sensitivity was 42.6% (26/61 positive, 95% CI 30.0-55.9), and specificity was 99.7% (1/289 positive, 95% CI 98.1-100). The agreement between the SARS-CoV-2 antigen and the RT-PCR cycle threshold (Ct) count was good (r = 0.90). In cases with Ct counts ≤ 30, the antigen assay sensitivity improved to 94.7% (18/19 positive, 95% CI 74.0-99.9). In our validation group, antigen sensitivity was 62.5% (5/8 antigen positive, 95% CI 24.5-91.5) within the first week of disease onset, but no cases were reactive after the first week of disease onset.
The Elecsys SARS-CoV-2 antigen assay has good performance within manufacturer specifications. The sensitivity of the Roche antigen assay was greatest when used in patients with lower RT-PCR Ct values (≤30) and within the first week of disease onset.
严重急性呼吸综合征冠状病毒2（SARS-CoV-2）抗原检测可作为逆转录聚合酶链反应（RT-PCR）检测的补充和替代方法。目前已有可扩展以同时处理大量2019冠状病毒病（COVID-19）病例的集中实验室自动化SARS-CoV-2抗原检测方法。我们对新型罗氏电化学发光免疫分析法Elecsys SARS-CoV-2抗原检测进行了评估。
罗氏SARS-CoV-2抗原检测是一种双抗体夹心电化学发光免疫分析法，报告截断指数（COI）（COI≥1.0视为阳性）。我们评估了检测的精密度和线性，并确定了反应性限度。我们使用一个验证组（289例对照和61例RT-PCR阳性的COVID-19病例）确定了检测的敏感性和特异性。还针对我们在2021年6月至10月期间收到的用于SARS-CoV-2抗原检测的连续样本（7657例对照和17例病例）验证了检测性能。
该检测在COI为0.68时批内精密度变异系数（CV）为3.0%，在COI为3.49时CV为1.5%。批间精密度在COI为0.68时为3.0%，在COI为3.49时为1.8%。该检测在COI为0.65至7.84之间呈线性。在7天内进行的所有35次C±20%检测结果分别为阳性/阴性。在验证组中，总体敏感性为42.6%（61例阳性中的26例，95%置信区间30.0 - 55.9），特异性为99.7%（289例阳性中的1例，95%置信区间98.1 - 100）。SARS-CoV-2抗原与RT-PCR循环阈值（Ct）计数之间的一致性良好（r = 0.90）。在Ct计数≤30的病例中，抗原检测敏感性提高到94.7%（19例阳性中的18例，95%置信区间74.0 - 99.9）。在我们的验证组中，发病第一周内抗原敏感性为62.5%（8例抗原阳性中的5例，95%置信区间24.5 - 91.5），但发病第一周后无病例呈反应性。
Elecsys SARS-CoV-2抗原检测在制造商规定的规格范围内具有良好性能。罗氏抗原检测在用于RT-PCR Ct值较低（≤30）且发病第一周内的患者时敏感性最高。
