Clinical application of combined detection of SARS-CoV-2-specific antibody and nucleic acid.

Background: The global outbreak of human severe acute respiratory syndrome coronavirus (SARS-CoV)-2 infection represents an urgent need for readily available, accurate and rapid diagnostic tests. Nucleic acid testing of respiratory tract specimens for SARS-CoV-2 is the current gold standard for diagnosis of coronavirus disease 2019 (COVID-19). However, the diagnostic accuracy of reverse transcription polymerase chain reaction (RT-PCR) tests for detecting SARS-CoV-2 nucleic acid may be lower than optimal. The detection of SARS-CoV-2-specific antibodies should be used as a serological non-invasive tool for the diagnosis and management of SARS-CoV-2 infection.

Aim: To investigate the diagnostic value of SARS-CoV-2 IgM/IgG and nucleic acid detection in COVID-19.

Methods: We retrospectively analyzed 652 suspected COVID-19 patients, and 206 non-COVID-19 patients in Wuhan Integrated TCM and Western Medicine Hospital. Data on SARS-CoV-2 nucleic acid tests and serum antibody tests were collected to investigate the diagnostic value of nucleic acid RT-PCR test kits and immunoglobulin (Ig)M/IgG antibody test kits. The 2 test was used to compare differences between categorical variables. A 95% confidence interval (CI) was provided by the Wilson score method. All analyses were performed with IBM SPSS Statistics version 22.0 (IBM Corp., Armonk, NY, United States).

Results: Of the 652 suspected COVID-19 patients, 237 (36.3%) had positive nucleic acid tests, 311 (47.7%) were positive for IgM, and 592 (90.8%) were positive for IgG. There was a significant difference in the positive detection rate between the IgM and IgG test groups ( < 0.001). Using the RT-PCR results as a reference, the specificity, sensitivity, and accuracy of IgM/IgG combined tests for SARS-CoV-2 infection were 98.5%, 95.8%, and 97.1%, respectively. Of the 415 suspected COVID-19 patients with negative nucleic acid test results, 366 had positive IgM/IgG tests with a positive detection rate of 88.2%.

Conclusion: Our data indicate that serological IgM/IgG antibody combined test had high sensitivity and specificity for the diagnosis of SARS-CoV-2 infection, and can be used in combination with RT-PCR for the diagnosis of SARS-CoV-2 infection.