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Updated: Oct 28, 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
Age significantly influences the sensitivity of SARS-CoV-2 rapid antibody assays
Natalie Irwin1, Lyle Murray1, Benjamin Ozynski2
1Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; Department of Medicine, Charlotte Maxeke Johannesburg Academic Hospital, Johannesburg, South Africa.
Background:
Point-of-care serological assays are a promising tool in COVID-19 diagnostics but do have limitations. Our study evaluated the sensitivity of five rapid antibody assays and explored factors influencing their sensitivity in detecting SARS-CoV-2-specific IgG and IgM antibodies.
Methods:
Finger-prick blood samples from 102 participants, within 2-6 weeks of PCR-confirmed COVID-19 diagnosis, were tested for IgG and IgM using five rapid serological assays. The assay sensitivities were compared, and patient factors evaluated in order to investigate potential associations with assay sensitivity.
Results:
Sensitivity ranged from 36% to 69% for IgG and 13% to 67% for IgM. Age was the only factor significantly influencing the likelihood of a detectable IgG or IgM response. Individuals aged 40 years and older had an increased likelihood of a detectable IgG or IgM antibody response by rapid antibody assay.
Conclusion:
Rapid serological assays demonstrate significant variability when used in a real-world clinical context. There may be limitations in their use for COVID-19 diagnosis among the young.
