tetano
Editor, Senior Moderator
Front Microbiol
. 2021 Dec 9;12:791489.
doi: 10.3389/fmicb.2021.791489. eCollection 2021.
Association of the Serum Levels of the Nucleocapsid Antigen of SARS-CoV-2 With the Diagnosis, Disease Severity, and Antibody Titers in Patients With COVID-19: A Retrospective Cross-Sectional Study
Rin Yokoyama[SUP] 1 [/SUP], Makoto Kurano[SUP] 1 2 [/SUP], Yuki Nakano[SUP] 1 [/SUP], Yoshifumi Morita[SUP] 1 [/SUP], Hiroko Ohmiya[SUP] 3 [/SUP], Yoshiro Kishi[SUP] 3 [/SUP], Jun Okada[SUP] 3 [/SUP], Chungen Qian[SUP] 4 [/SUP], Fuzhen Xia[SUP] 5 [/SUP], Fan He[SUP] 5 [/SUP], Liang Zheng[SUP] 5 [/SUP], Yi Yu[SUP] 5 [/SUP], Miyuki Mizoguchi[SUP] 6 [/SUP], Yoshimi Higurashi[SUP] 6 [/SUP], Sohei Harada[SUP] 6 [/SUP], Daisuke Jubishi[SUP] 6 [/SUP], Koh Okamoto[SUP] 6 [/SUP], Kyoji Moriya[SUP] 6 [/SUP], Tatsuhiko Kodama[SUP] 7 [/SUP], Yutaka Yatomi[SUP] 1 2 [/SUP]
Affiliations
Abstract
Background: Several types of laboratory tests for COVID-19 have been established to date; however, the clinical significance of the serum SARS-CoV-2 nucleocapsid (N) antigen levels remains to be fully elucidated. In the present study, we attempted to elucidate the usefulness and clinical significance of the serum N antigen levels. Methods: We measured the serum N antigen levels in 391 serum samples collected from symptomatic patients with a confirmed diagnosis of COVID-19 and 96 serum samples collected from patients with non-COVID-19, using a fully automated chemiluminescence immunoassay analyzer. Results: Receiver operating characteristic analysis identified the optimal cutoff value of the serum N antigen level (cutoff index, based on Youden's index) as 0.255, which yielded a sensitivity and specificity for the diagnosis of COVID-19 of 91.0 and 81.3%, respectively. The serum N antigen levels were significantly higher in the patient groups with moderate and severe COVID-19 than with mild disease. Moreover, a significant negative correlation was observed between the serum N antigen levels and the SARS-CoV-2 IgG antibody titers, especially in patients with severe COVID-19. Conclusion: Serum N antigen testing might be useful both for the diagnosis of COVID-19 and for obtaining a better understanding of the clinical features of the disease.
Keywords: COVID-19; N antigen; antibody titer; coronavirus disease 2019; diagnosis; nucleocapsid antigen; severity.
. 2021 Dec 9;12:791489.
doi: 10.3389/fmicb.2021.791489. eCollection 2021.
Association of the Serum Levels of the Nucleocapsid Antigen of SARS-CoV-2 With the Diagnosis, Disease Severity, and Antibody Titers in Patients With COVID-19: A Retrospective Cross-Sectional Study
Rin Yokoyama[SUP] 1 [/SUP], Makoto Kurano[SUP] 1 2 [/SUP], Yuki Nakano[SUP] 1 [/SUP], Yoshifumi Morita[SUP] 1 [/SUP], Hiroko Ohmiya[SUP] 3 [/SUP], Yoshiro Kishi[SUP] 3 [/SUP], Jun Okada[SUP] 3 [/SUP], Chungen Qian[SUP] 4 [/SUP], Fuzhen Xia[SUP] 5 [/SUP], Fan He[SUP] 5 [/SUP], Liang Zheng[SUP] 5 [/SUP], Yi Yu[SUP] 5 [/SUP], Miyuki Mizoguchi[SUP] 6 [/SUP], Yoshimi Higurashi[SUP] 6 [/SUP], Sohei Harada[SUP] 6 [/SUP], Daisuke Jubishi[SUP] 6 [/SUP], Koh Okamoto[SUP] 6 [/SUP], Kyoji Moriya[SUP] 6 [/SUP], Tatsuhiko Kodama[SUP] 7 [/SUP], Yutaka Yatomi[SUP] 1 2 [/SUP]
Affiliations
- PMID: 34956158
- PMCID: PMC8696188
- DOI: 10.3389/fmicb.2021.791489
Abstract
Background: Several types of laboratory tests for COVID-19 have been established to date; however, the clinical significance of the serum SARS-CoV-2 nucleocapsid (N) antigen levels remains to be fully elucidated. In the present study, we attempted to elucidate the usefulness and clinical significance of the serum N antigen levels. Methods: We measured the serum N antigen levels in 391 serum samples collected from symptomatic patients with a confirmed diagnosis of COVID-19 and 96 serum samples collected from patients with non-COVID-19, using a fully automated chemiluminescence immunoassay analyzer. Results: Receiver operating characteristic analysis identified the optimal cutoff value of the serum N antigen level (cutoff index, based on Youden's index) as 0.255, which yielded a sensitivity and specificity for the diagnosis of COVID-19 of 91.0 and 81.3%, respectively. The serum N antigen levels were significantly higher in the patient groups with moderate and severe COVID-19 than with mild disease. Moreover, a significant negative correlation was observed between the serum N antigen levels and the SARS-CoV-2 IgG antibody titers, especially in patients with severe COVID-19. Conclusion: Serum N antigen testing might be useful both for the diagnosis of COVID-19 and for obtaining a better understanding of the clinical features of the disease.
Keywords: COVID-19; N antigen; antibody titer; coronavirus disease 2019; diagnosis; nucleocapsid antigen; severity.