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Diagnostic Value of Nucleocapsid Protein in Blood for SARS-CoV-2 Infection
- Source :
- Clinical Chemistry
- Publication Year :
- 2021
- Publisher :
- Oxford University Press (OUP), 2021.
-
Abstract
- Background Biomarkers have been widely explored for coronavirus disease 2019 diagnosis. Both viral RNA or antigens (Ag) in the respiratory system and antibodies (Ab) in blood are used to identify active infection, transmission risk, and immune response but have limitations. This study investigated the diagnostic utility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid protein (N-Ag) in serum. Methods We retrospectively studied 208 randomly selected cases with SARS-CoV-2 infection confirmed by viral RNA test in swabs. N-Ag concentrations were measured in remnant serum samples, compared to viral RNA or Ab results, and correlated to electronic health records for clinical value evaluation. Results Serum N-Ag was detected during active infection as early as day 2 from symptom onset with a diagnostic sensitivity of 81.5%. Within 1 week of symptom onset, the diagnostic sensitivity and specificity reached 90.9% (95% CI, 85.1%–94.6%) and 98.3% (95% CI, 91.1%–99.9%), respectively. Moreover, serum N-Ag concentration closely correlated to disease severity, reflected by highest level of care, medical interventions, chest imaging, and the length of hospital stays. Longitudinal analysis revealed the simultaneous increase of Abs and decline of N-Ag. Conclusions Serum N-Ag is a biomarker for SARS-CoV-2 acute infection with high diagnostic sensitivity and specificity compared to viral RNA in the respiratory system. There is a correlation between serum N-Ag concentrations and disease severity and an inverse relationship of N-Ag and Abs. The diagnostic value of serum N-Ag, as well as technical and practical advantages it could offer, may meet unsatisfied diagnostic and prognostic needs during the pandemic.
- Subjects :
- medicine.medical_specialty
Coronavirus disease 2019 (COVID-19)
Evidence-based Medicine and Test Utilization (TUO)
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)
Clinical Biochemistry
Antibodies, Viral
Sensitivity and Specificity
Gastroenterology
COVID-19 Testing
Immune system
Antigen
serum nucleocapsid protein
Internal medicine
medicine
Coronavirus Nucleocapsid Proteins
Humans
Respiratory system
Retrospective Studies
biology
SARS-CoV-2
Transmission (medicine)
business.industry
Biochemistry (medical)
COVID-19
Nucleocapsid Proteins
Phosphoproteins
AcademicSubjects/SCI01290
biology.protein
RNA, Viral
biomarker
Biomarker (medicine)
AcademicSubjects/MED00530
AcademicSubjects/SCI00980
Antibody
business
AcademicSubjects/MED00690
Subjects
Details
- ISSN :
- 15308561 and 00099147
- Volume :
- 68
- Database :
- OpenAIRE
- Journal :
- Clinical Chemistry
- Accession number :
- edsair.doi.dedup.....0354e387b0d08d04ca1b30410b76f052