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Updated: Dec 14, 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
Concordance between two rapid diagnostic tests for the detection of antibodies against SARS-CoV-2
Jaime de la Iglesia1, Tania Fernández-Villa2, Juan M Fegeneda-Grandes3
1Especialista en Medicina Familiar y Comunitaria. Centro de salud Condesa, León.
Objective:
To assess the agreement between two rapid detection tests (RDT) for antibodies against SARS-CoV-2 infection.
Materials And Methods:
This was a cross-sectional study that used a random sample of non-hospitalized patients from the primary care management division of the Healthcare Area of Leon (58 RT-PCR-positive cases and 52 RT-PCR-negative cases). Information regarding symptoms was collected and all patients were simultaneously tested using two RDTs (Combined - cRDT and Differentiated - dRDT). The results of both tests were evaluated using the chi-square test and, for degree of agreement, the kappa coefficient.
Results:
About 52% of the participants were women (mean age: 48.2±11.0 years). A total of 58.2% were positive for d-RDT and 41.2% were positive for c-RDT. In the subjects who were RT-PCR-positive, d-RDT was positive in 72.4% and c-RDT in 55.2%; in those who were RT-PCR-negative, the percentages were 42.3% and 26.9%, respectively. The kappa coefficient observed between the two RDTs was 0.644, and was higher in patients without a fever or anosmia (0.725) and lower in those with a fever or anosmia (0.524).
Conclusions:
There is good agreement between the tests used in this study. Given the sensitivity observed, they can be very useful as a complement to RT-PCR.
