Department of Clinical Laboratory, The First Affiliated Hospital of Anhui Medical University, Hefei, China.
Key Laboratory of Anti-inflammatory and Immune Medicine, Ministry of Education, Anhui Collaborative Innovation Center of Anti-inflammatory and Immune Medicine, Anhui Anti-inflammatory and Immune Medicine Innovation Team, Institute of Clinical Pharmacology, Anhui Medical University, Hefei, China.
Front Cell Infect Microbiol. 2020 Sep 4;10:470. doi: 10.3389/fcimb.2020.00470. eCollection 2020.
To explore the diagnostic value of serum severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid (N) protein assay in the early stages of SARS-COV-2 infection. Serum N protein level in SARS-COV-2 infected patients and non-SARS-COV-2 infected population was measured by enzyme-linked immunosorbent assay (ELISA) double antibody sandwich assay. Colloidal gold immunochromatography assay was used to detect serum N protein antibodies in the above populations. Fifty cases of SARS-CoV-2 nucleic acid-positive and SARS-CoV-2 antibody-negative patients had a serum N protein positivity rate of 76%. Thirty-seven patients who were positive for serum SARS-CoV-2 antibody after infection had a serum SARS-CoV-2 N protein positivity rate of 2.7%. Serum N protein test results of 633 non-SARS-COV-2 infected patients, including pregnant women, patients with other respiratory infections, and individuals with increased rheumatoid factor were all negative, with serum N protein concentration <10.00 pg/mL at 100% specificity. Using SPSS 19.0 to calculate the receiver operating characteristic curve, the area under the curve was determined to be 0.9756 (95% confidence interval 0.9485-1.000, < 0.0001), and sensitivity and specificity were 92% (95% confidence interval 81.16-96.85%) and 96.84% (95% confidence interval 95.17-97.15%), respectively. The best CUT-OFF value was 1.850 pg/mL. The measurement of serum SARS-COV-2 N protein has a high diagnostic value for infected patients before the antibody appears and shortens the window period of serological diagnosis. It is recommended that the manufacturer establish two different CUT-OFF values according to the purpose of the application. One CUT-OFF value is used for the diagnosis of clinical SARS-COV-2 infection, and the other is used to screen out as many suspected cases as possible.
探讨血清严重急性呼吸综合征冠状病毒 2（SARS-CoV-2）核衣壳（N）蛋白检测在 SARS-CoV-2 感染早期的诊断价值。采用酶联免疫吸附试验（ELISA）双抗体夹心法检测 SARS-CoV-2 感染患者和非 SARS-CoV-2 感染人群血清 N 蛋白水平。胶体金免疫层析法检测上述人群血清 N 蛋白抗体。50 例 SARS-CoV-2 核酸阳性且 SARS-CoV-2 抗体阴性患者的血清 N 蛋白阳性率为 76%。37 例感染后血清 SARS-CoV-2 抗体阳性患者的血清 SARS-CoV-2 N 蛋白阳性率为 2.7%。633 例非 SARS-CoV-2 感染患者，包括孕妇、其他呼吸道感染患者和类风湿因子升高者的血清 N 蛋白检测结果均为阴性，血清 N 蛋白浓度均<10.00pg/ml，特异性为 100%。采用 SPSS 19.0 计算受试者工作特征曲线，确定曲线下面积为 0.9756（95%置信区间 0.9485-1.000，<0.0001），灵敏度和特异度分别为 92%（95%置信区间 81.16-96.85%）和 96.84%（95%置信区间 95.17-97.15%）。最佳截断值为 1.850pg/ml。血清 SARS-CoV-2 N 蛋白检测对抗体出现前感染患者具有较高的诊断价值，缩短了血清学诊断的窗口期。建议厂家根据应用目的建立两个不同的截断值。一个截断值用于临床 SARS-CoV-2 感染的诊断，另一个用于尽可能筛选出更多的疑似病例。
