"The effectiveness of rapid antigen test-based for SARS-CoV-2 detection in nursing homes in Valencia, Spain".

ABSTRACT

The usefulness of the PANBIO ™ COVID-19 Ag rapid test for SARS-CoV-2 infection detection has not been widely studied, especially in specific population groups such as the elderly who are institutionalized. Rapid diagnostic tests have the potential to benefit testing strategies, as they have short turnaround times, they are cheap, simple to perform and can be used in decentralized testing. The objective of this study is to show the performance of the PANBIO™ COVID-19 Ag Rapid test device conducted at geriatric institutions and to compare results to those obtained from RT-PCR. A total of 448 individuals were enrolled in the study, including both residents and employees. Nasopharyngeal swabs were collected for both PANBIO™ COVID-19 Ag Rapid test and RT-PCR testing. All the samples were analyzed by specialized microbiologists. A total of 117 out of 448 individuals (26%) tested positive by RT-PCR, of whom 99 (85%) returned positive Antigen test results. There were 18 Antigen negative cases with positive RT-PCR results. Accordingly, concordance between RT-PCR and Antigen test results was acceptable (K index, 0.89; 95% IC 0.8455-0.9345). Overall sensitivity and specificity of Antigen test was 85% and 100%, respectively. When defining RT-PCR CT positivity on a cut-off value of 35, LFA sensitivity was 90%. In case a cut-off value of 30 was used, LFA would increase up to 99%. In this real-life evaluation of the PANBIO™ COVID-Ag rapid test, the assay reliably identified SARS-CoV-2 infected individuals with low CT-values by RT-PCR. False negative results were observed only at high CT-values, meaning low viral loads in nasopharyngeal samples.