Concordance between two rapid diagnostic tests for the detection of antibodies against SARS-CoV-2 / Concordancia entre dos pruebas de detección rápida para la exploración de anticuerpos contra el SARS-CoV-2

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

OBJETIVO: Evaluar la concordancia entre dos pruebas de detección rápida (PDR) de anticuerpos en la infección por SARS-CoV-2. MATERIALES Y MÉTODOS: Estudio transversal. Se utilizó una muestra aleatoria de pacientes no hospitalizados de la Gerencia de Atención Primaria del Área de Salud de León (58 con RT-PCR positiva y 52 con RT-PCR negativa). Se recogió información sobre síntomas y a todos se les realizó simultáneamente dos PDR (combinada: PRD-C y diferenciada: PRD-D). Los resultados de ambas pruebas fueron evaluados mediante X2 y el grado de concordancia con el índice Kappa. RESULTADOS: Un 52% de los participantes fueron mujeres (edad media: 48,2 ± 11,0 años). El 58,2% fue positivo a la PDR-D y 41,2% a la PDR-C. En los sujetos RT-PCR + la PDR-D fue positiva en el 72,4% y la PDR-C en el 55,2%; en el caso de los RT-PCR - en el 42,3% y 26,9%, respectivamente. El índice Kappa observado entre las dos PDR fue del 0,644, siendo mayor en pacientes sin fiebre ni anosmia (0,725) y menor en aquellos con fiebre o anosmia (0,524). CONCLUSIONES: Existe una buena concordancia entre los test utilizados en este estudio. Dada la sensibilidad obtenida, pueden ser de gran utilidad como complemento a las RT-PCR

Concordance between two rapid diagnostic tests for the detection of antibodies against SARS-CoV-2.

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.