Diagnostic Performance of Ag-RDTs and NAAT for SARS-CoV2 Identification in Symptomatic Patients in Catalonia.

Luca Basile,Jacobo Mendioroz Peña,Víctor Guadalupe-Fernández,Ana Martinez Mateo,Pilar Ciruela Navas,Manuel Valdivia Guijarro

doi:10.3390/v13050908

Abstract

The use of rapid antigenic tests (Ag-RDTs) to diagnose a SARS-CoV-2 infection has become a common practice recently. This study aimed to evaluate performance of Abbott PanbioTM Ag-RDTs with regard to nucleic acid amplification testing (NAAT) in the early stages of the disease. A cohort of 149,026 infected symptomatic patients, reported in Catalonia from November 2020 to January 2021, was selected. The positivity rates of the two tests were compared with respect to the dates of symptom onset. Ag-RDTs presented positivity rates of 84% in the transmission phases of the disease and 31% in the pre-symptomatic period, compared to 93% and 91%, respectively, for NAAT. The detection of many false negatives with Ag-RDTs during the pre-symptomatic period demonstrates the risk of virus dissemination with this diagnostic technique if used outside the symptomatic period.

Highlights

Due to its high sensitivity and specificity, nucleic acid amplification testing (NAAT) has become the gold standard for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [1]
Data were analyzed from the Epidemiological Repository of Catalonia (REC), an electronic registry used by the Catalonian Epidemiological Surveillance Network (XVEC) which automatically receives results of Ag-RDTs, NAAT and serological tests from National Health Service laboratories, and from several private entities
According to current guidelines on the use of Ag-RDTs [11], authorized Ag-RDTs, and especially Abbott PanbioTM, have reported consistently high levels of specificity, but they do not achieve equal levels of sensitivity compared to NAAT [12,13]

Summary

Introduction

Due to its high sensitivity and specificity, nucleic acid amplification testing (NAAT) has become the gold standard for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) [1]. In December 2020, the European Union adopted a common response for the use, validation and recognition of Ag-RDTs as a diagnostic method to detect SARS-CoV-2 infection [6]. The European Centre for Disease and Control (ECDC) agreed on a selected list of validated Ag-RDTs along with recommendations on their use for the diagnosis of COVID-19, based on the best available evidence to date, from systematic research of clinical trials [4]. PanbioTM COVID-19 Ag Rapid Test Device (Abbott Diagnostics, Jena, Germany) started to be used massively in Catalonian primary care centers and hospitals at the end of October

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