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Updated: Aug 7, 2025
A Rapid, Multiplex Dual Reporter IgG and IgM SARS-CoV-2 Neutralization Assay for a Multiplexed Bead-Based Flow Analysis System
Published on: April 6, 2021
Diagnostic Performance of Interferon Gamma Release Assay (IGRA) for Cell-Mediated Immune Responses to SARS-CoV-2
Background:
As SARS-CoV-2 infection became a pandemic, much effort has been made to measure both antibody production and T cell response to SARS-CoV-2 to diagnose COVID-19 patients or find out their immune status. Authors tried to determine the optimal cutoff value and evaluate clinical performance of one interferon-γ release assay (IGRA) kit and compared their results with serological antibody assay in COVID-19 patients.
Methods:
Study subjects included 100 patients confirmed as COVID-19 with RT-PCR method and 88 healthy volunteers who were PCR negative. IGRA tests were performed using STANDARDTM E Covi-FERON ELISA. Presence of SARS-CoV-2 antibodies was detected using STANDARD Q COVID-19 IgM/IgG Plus Test. Cutoff value was assessed using receiver operating characteristic (ROC) curve.
Results:
The cutoff value was 0.24 IU/mL and the area under the curve (AUC) of the ROC curve was 0.973 with 95% confidence interval (CI) of 0.940 - 1.005. At this cutoff value, sensitivity and specificity were 91.7% and 100%, respectively. In addition, when compared with antibody test, concordance rate was 95%.
Conclusions:
STANDARDTM E Covi-FERON ELISA showed high sensitivity and specificity, when the cutoff value was 0.24 IU/mL. It was also consistent with the antibody test. IGRA test was a good indicator of cellular immune response in COVID-19 patients.
