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Updated: Dec 24, 2025
Dynamic Monitoring of Seroconversion using a Multianalyte Immunobead Assay for Covid-19
Published on: February 16, 2022
Diagnostic value and dynamic variance of serum antibody in coronavirus disease 2019
Yujiao Jin1, Miaochan Wang1, Zhongbao Zuo1
1Department of Clinical Laboratory, Xixi Hospital of Hangzhou, Hangzhou 310023, Zhejiang, China.
Insights
Serological testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) shows high diagnostic value. Immunoglobulin G (IgG) antibody levels are more indicative of COVID-19 infection than Immunoglobulin M (IgM) over time.
Area of Science:
- Infectious Diseases
- Immunology
- Diagnostic Medicine
Background:
- Coronavirus disease 2019 (COVID-19) diagnosis relies on various methods.
- Understanding the dynamics of antibody responses is crucial for accurate diagnosis and patient management.
Purpose of the Study:
- To evaluate the diagnostic utility of serological tests for COVID-19.
- To analyze the dynamic changes in serum IgM and IgG antibody titers in SARS-CoV-2 infected patients.
Main Methods:
- Retrospective study of 43 laboratory-confirmed COVID-19 cases and 33 suspected cases.
- Chemiluminescence immunoassay used to measure serum IgM and IgG titers against SARS-CoV-2.
Main Results:
- IgG antibody testing demonstrated higher sensitivity (88.9%) and specificity (90.9%) compared to IgM (48.1% sensitivity, 100% specificity) for COVID-19 diagnosis.
- IgG antibody levels remained elevated and showed a significant increase post-viral clearance, unlike IgM levels.
Conclusions:
- Serological testing is an effective diagnostic tool for SARS-CoV-2 infections.
- IgG antibody response is more robust and sustained than IgM in COVID-19 patients.
Objective:
To investigate the diagnostic value of serological testing and dynamic variance of serum antibody in coronavirus disease 2019 (COVID-19).
Methods:
This study retrospectively included 43 patients with a laboratory-confirmed infection and 33 patients with a suspected infection, in whom the disease was eventually excluded. The IgM/IgG titer of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was measured by chemiluminescence immunoassay analysis.
Results:
Compared to molecular detection, the sensitivities of serum IgM and IgG antibodies to diagnose COVID-19 were 48.1% and 88.9%, and the specificities were 100% and 90.9%, respectively.In the COVID-19 group, the IgM-positive rate increased slightly at first and then decreased over time; in contrast, the IgG-positive rate increased to 100% and was higher than IgM at all times. The IgM-positive rate and titer were not significantly different before and after conversion to virus-negative. The IgG-positive rate was up to 90% and not significantly different before and after conversion to virus-negative. However, the median IgG titer after conversion to virus-negative was double that before, and the difference was significant.
Conclusions:
Viral serological testing is an effective means of diagnosis for SARS-CoV-2 infection. The positive rate and titer variance of IgG are higher than those of IgM in COVID-19.
