Comparison of Serologic Response of Hospitalized COVID-19 Patients Using 8 Immunoassays

Background: In Korea, there were issues regarding the use of immunoassays for anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies to detect infection. So, we compared antibody results of eight kinds of commercial immunoassays using clinical remnant specimens. Methods: We compared the results of several immunoassay kits tested on 40 serum samples from 15 confirmed patients and 86 remnant serum samples from clinical laboratory. Eight kinds of IVD kits-four enzyme-linked immunosorbent assay, two lateral flow rapid immunochromatographic assays, and two chemiluminescent immunoassays with one RUO kit were tested. Results: Among 40 serum samples from 15 coronavirus disease 2019 (COVID-19) patients, 35 yielded at least one positive result for detecting antibodies in the combined assessment. There were inconsistent results in 12 (28%) samples by single immunoassay. Forty samples collected in 2019 before the first COVID-19 Korean case showed negative results except for one equivocal result. Conclusion: The discrepant results obtained with different immunoassay kits in this study show that serological assessment of SARS- CoV-2 by a single immunoassay requires caution not only in detecting infection but also in assessing immunologic status.

Automated summary

The study in Korea highlighted discrepancies in antibody detection for SARS-CoV-2 using different immunoassay kits, indicating the need for caution when relying on results from a single immunoassay for both infection detection and immunologic status assessment.