In December, the outbreak of a novel coronavirus (2019-nCoV) in Wuhan, China, has attracted extensive global attention. On January 20, 2020,the Chinese health authorities upgraded the coronavirus to a Class B infectious disease in the Law of the People's Republic of China on the Prevention and Treatment of Infectious Diseases, and considered it as Class A infectious diseases in disease control and prevention. On January 22, 2020, the 2019-nCoV nucleic acid detection test was listed as the diagnostic criteria in the "guidelines for diagnosis and treatment of pneumonia due to 2019-nCoV (Trial Version 2)" . Therefore, standardizing the operation process of the 2019-nCoV nucleic acid detection in clinical laboratories has become a top priority. It is of paramount importance to establish standard protocols for detection of the 2019-nCoV nucleic acids in clinical laboratories to improve the reliability of the results and ensure the biosafety of laboratory personnel.

Objective:To investigate the diagnostic value of immunoglobulin M (IgM) and immunoglobulin G(IgG) antibodies to 2019 Novel Coronavirus (2019-nCoV) in 2019-nCoV infection.Methods:This is a retrospective study. Serum samples were collected from 284 patients including outpatients and inpatients in the Renmin Hospital of Wuhan University from January 20 to February 17 in 2020. Among them 205 cases were 2019-nCoV infected patients, including 186 cases confirmed with nucleic acid test and 19 cases diagnosed by clinical symptoms and CT characteristics according to "the New Coronavirus Pneumonia Control Protocol (5th edition)" . A total of 79 subjects with other diseases but negative to 2019-nCoV infection were recruited as control group. Serum IgM and IgG antibodies to 2019-nCoV were measured with fully automated immunoassay technology for all subjects. Statistical significance between 2019-nCoV antibodies test and 2019-nCoV nucleic acid test was determined using the χ 2 tests. Results:The sensitivity of serum IgM and IgG antibodies to 2019-nCoV were 70.24%(144/205) and 96.10%(197/205) respectively and the specificity were 96.20%(76/79) and 92.41%(73/79) respectively. The positive and negative predictive values of 2019-nCoV antibodies were 95.63%(197/206) and 91.03% (71/78) respectively, and the positive and negative predictive values of 2019-nCoV nucleic acid test were 100%(186/186) and 80.61%(79/98) respectively. The total coincidence rate of diagnosing 2019-nCoV infection between antibody tests and nucleic acid test for 2019-nCoV were 88.03%(250/284).Conclusion:Joint detection of serum IgM and IgG antibodies to 2019-nCoV is an effective screening and diagnostic indicators for 2019-nCoV infection, and an effective complement to the false negative results to nucleic acid test.

In December, the outbreak of a novel coronavirus (2019-nCoV) in Wuhan, China, has attracted extensive global attention. On January 20, 2020, the Chinese health authorities upgraded the coronavirus to a Class B infectious disease in the Law of the People′s Republic of China on the Prevention and Treatment of Infectious Diseases, and considered it as Class A infectious diseases in disease control and prevention. On January 18, 2020, the 2019-nCoV nucleic acid detection test was listed as the diagnostic criteria in the "guidelines for diagnosis and treatment of pneumonia due to 2019-nCoV (Trial Version 2)" . Therefore, standardizing the operation process of the 2019-nCoV nucleic acid detection in clinical laboratories has become a top priority. It is of paramount importance to establish standard protocols for detection of the 2019-nCoV nucleic acids in clinical laboratories to improve the reliability of the results and ensure the biosafety of laboratory personnel.

Objective: To investigate the diagnostic value of immunoglobulin M (IgM) and immunoglobulin G(IgG) antibodies to 2019 Novel Coronavirus (2019-nCoV) in 2019-nCoV infection. Method: This is a retrospective study. Serum samples were collected from 284 patients including outpatients and inpatients in the Renmin Hospital of Wuhan University from January 20, 2020 to February 17, 2020. Among them 205 cases were 2019-nCoV infected patients, including 186 cases confirmed with nucleic acid test and 19 cases diagnosed by clinical symptoms and CT characteristics according to "the New Coronavirus Pneumonia Control Protocol (5th edition)" . A total of 79 subjects with other diseases but negative to 2019-nCoV infection were recruited as control group. Serum IgM and IgG antibodies to 2019-nCoV were measured with fully automated immunoassay technology for all subjects. Statistical significance between 2019-nCoV antibodies test and 2019-nCoV nucleic acid test was determined using the χ² tests. Result: The sensitivity of serum IgM and IgG antibodies to 2019-nCoV were 70.24%(144/205) and 96.10%(197/205) respectively and the specificity were 96.20%(76/79) and 92.41%(73/79) respectively. The positive and negative predictive values of 2019-nCoV antibodies were 95.63%(197/206) and 91.03% (71/78) respectively, and the positive and negative predictive values of 2019-nCoV nucleic acid test were 100%(186/186) and 80.61%(79/98) respectively. The total coincidence rate of diagnosing 2019-nCoV infection between antibody tests and nucleic acid test for 2019-nCoV were 88.03%(250/284). Conclusion Joint detection of serum IgM and IgG antibodies to 2019-nCoV is an effective screening and diagnostic indicators for 2019-nCoV infection, and an effective complement to the false negative results to nucleic acid test.