The utility of SARS-CoV-2 nucleocapsid protein in laboratory diagnosis

The Coronavirus Disease 2019 (COVID-19) is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which has now become a global pandemic owing to its high transmissibility. The SARS-CoV-2 nucleocapsid protein tests are playing an important role in screening and diagnosing patients with COVID-19, and studies about the utility of SARS-CoV-2 nucleocapsid protein tests are increasing now.

In this review, all the relevant original studies were assessed by searching in electronic databases including Scopus, Pubmed, Embase, and Web of Science. "SARS-CoV-2", "COVID-19", "nucleocapsid protein", and "antigen detection" were used as keywords.

In this review, we summarized the utility of SARS-CoV-2 nucleocapsid protein in laboratory diagnosis. Among the representative researches, this review analyzed, the sensitivity of SARS-CoV-2 nucleocapsid protein detection varies from 13% to 87.9%, while the specificity could almost reach 100% in most studies. As a matter of fact, the sensitivity is around 50% and could be higher or lower due to the influential factors.

It is well suggested that SARS-CoV-2 nucleocapsid protein is a convenient method with a short turnaround time of about half an hour, and the presence of N antigen is positively related to viral transmissibility, indicating that SARS-CoV-2 N protein immunoassays contribute to finding out those infected people rapidly and segregating them from the uninfected people.