Diagnostic value and characteristic analysis of serum nucleocapsid antigen in COVID-19 patients

PeerJ

article

Xihong Zhang¹  Chungen Qian³  Li Yang²  Huixia Gao²  Ping Jiang⁴  Muwei Dai⁵  Yuling Wang⁴  Haiyan Kang⁴  Yi Xu²  Qian Hu²  Fumin Feng¹  Bangning Cheng⁶  Erhei Dai² 

[1] School of Public Health, North China University of Science and Technology;Department of Laboratory Medicine, The Fifth Hospital of Shijiazhuang, North China University of Science and Technology;The Key Laboratory for Biomedical Photonics of MOE at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology;Department of Tuberculosis, The Fifth Hospital of Shijiazhuang, North China University of Science and Technology;Orthopaedic Department, The Fourth Hospital of Hebei Medical University and Hebei Cancer Hospital;Shenzhen YHLO Biotech Co., Ltd

关键词: SARS-CoV-2;    COVID-19;    Nucleocapsid antigen;    Diagnosis;    Serum;   

DOI  :  10.7717/peerj.15515

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Background To date, several types of laboratory tests for coronavirus disease 2019 (COVID-19) diagnosis have been developed. However, the clinical importance of serum severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid antigen (N-Ag) remains to be fully elucidated. In this study, we sought to investigate the value of serum SARS-CoV-2 N-Ag for COVID-19 diagnosis and to analyze N-Ag characteristics in COVID-19 individuals. Methods Serum samples collected from 215 COVID-19 patients and 65 non-COVID-19 individuals were used to quantitatively detect N-Ag via chemiluminescent immunoassay according to the manufacturer’s instructions. Results The sensitivity and specificity of the N-Ag assay were 64.75% (95% confidence interval (95% CI) [55.94–72.66%]) and 100% (95% CI [93.05–100.00%]), respectively, according to the cut-off value recommended by the manufacturer. The receiver operating characteristic (ROC) curve showed a sensitivity of 100.00% (95% CI [94.42–100.00%]) and a specificity of 71.31% (95% CI [62.73–78.59%]). The positive rates and levels of serum SARS-CoV-2 N-Ag were not related to sex, comorbidity status or disease severity of COVID-19 (all P < 0.001). Compared with RT‒PCR, there was a lower positive rate of serum N-Ag for acute COVID-19 patients (P < 0.001). The positive rate and levels of serum SARS-CoV-2 N-Ag in acute patients were significantly higher than those in convalescent patients (all P < 0.001). In addition, the positive rate of serum SARS-CoV-2 N-Ag in acute COVID-19 patients was higher than that of serum antibodies (IgM, IgG, IgA and neutralizing antibodies (Nab)) against SARS-CoV-2 (all P < 0.001). However, the positive rate of serum SARS-CoV-2 N-Ag in convalescent COVID-19 patients was significantly lower than that of antibodies (all P < 0.001). Conclusion Serum N-Ag can be used as a biomarker for early COVID-19 diagnosis based on appropriate cut-off values. In addition, our study also demonstrated the relationship between serum N-Ag and clinical characteristics.

【 授权许可】

CC BY