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Updated: Jul 27, 2026

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
Performance assessment of 11 commercial serological tests for SARS-CoV-2 on hospitalised COVID-19 patients
C Serre-Miranda1, C Nobrega1, S Roque1
1Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal; ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal.
Background:
Commercial availability of serological tests to evaluate immunoglobulins (Ig) targeting severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has grown exponentially since the start of the coronavirus disease 2019 (COVID-19) outbreak. Thorough validation of these tests is important before use as epidemiological tools to infer seroprevalence in specific populations and as diagnostic tools to complement molecular approaches (e.g., quantitative reverse transcription-polymerase chain reaction).
Methods:
Commercial serological tests from 11 suppliers were assayed side-by-side using 126 samples from SARS-CoV-2-infected inpatients and 36 from healthy and HIV-infected individuals.
Results:
The majority of the tests assayed have >95% specificity. For the sensitivity calculation, samples were stratified by days since symptoms onset; sensitivity peaks at 16-21 days for IgM and IgA (maximum 91.2%, Euroimmun) and, dependant on the test, at 16-21 or >21 days for IgG (maximum 94.1%, Snibe). Data from semiquantitative tests show that patients with a severe clinical presentation have lower levels of Ig targeting SARS-CoV-2 at <10 days since symptoms onset and higher levels at >21 days, compared to patients with a non-severe presentation.
Conclusions:
This study highlights the heterogeneity of sensitivity and generally high specificity of the serological tests and establishes a basis for their usefulness to complement diagnostic techniques and population seroprevalence studies.

