Evaluation of the performance of SARS-CoV-2 antigen detection kits

Abstract

Introduction: Recent efforts in the diagnosis of SARS-CoV-2 have focused on the development of rapid tests for the detection of SARS-CoV-2 antigens (RTD-Ag), due to the low cost of these methods and the speed to provide a primary diagnosis at the point of care outside the laboratory. In this study, the utility of five methods for detecting the nucleocapsid protein (N) of SARS-CoV-2 as an antigen (Ag) for the positive diagnosis of this virus was evaluated.

Methods: Five kits for the detection of SARS-CoV-2 Ag based on two molecular principles (immunochromatography and immunofluorescence) were evaluated. A total of 587 samples from nasal and nasopharyngeal swab of patients confirmed by RT-PCR to SARS-CoV-2 and negative samples to this virus were analyzed. Sensitivity, specificity, Positive Predictive Value (PPV), Negative Predictive Value (NPV), concordance and Kappa index parameters were calculated for each assay evaluated.

Results: The ABBOTT, CPM, CORE and WANTAI SARS-CoV-2 (IFA) assays performed well (sensitivity: 80-95 % and specificity 90-98 %) when evaluated with samples from suspected patients. In the KEWEI trial, the results of these parameters differed (75 % sensitivity and 90 % specificity) from those recommended by the WHO. According to the Kappa index rating scale, all the trials analyzed showed good and very good agreement.

Conclusions: The results obtained in this research support the utility of the tests evaluated and their use in the network of laboratories for the diagnosis of SARS-CoV-2.