Comparison of the quidel sofia SARS FIA test to the hologic aptima SARS-CoV-2 TMA test for diagnosis of COVID-19 in symptomatic outpatients

Abstract

The Quidel Sofia severe acute respiratory syndrome (SARS) fluorescent immunoassay (FIA) test (SOFIA) is a rapid antigen immunoassay for the detection of SARS coronavirus 2 (SARS-CoV-2) proteins from nasal or nasopharyngeal swab specimens. The purpose of this study was to compare the results of the SOFIA test to those of the Hologic Aptima SARS-CoV-2 TMA test (APTIMA TMA), a high-throughput molecular diagnostic test that uses transcription-mediated amplification (TMA) for the detection of SARS-CoV-2 nucleic acid from upper respiratory tract specimens. Three hundred forty-seven symptomatic patients from an urgent care center in an area with a high prevalence of SARS-CoV-2 infections were tested in parallel using nasal swabs for the SOFIA test and nasopharyngeal swabs for the APTIMA TMA test. The SOFIA test demonstrated a positive percent agreement (PPA) of 82.0% with the APTIMA TMA test for symptomatic patients tested#5days from symptom onset and a PPA of 54.5% for symptomatic patients.5days from symptom onset. The Cepheid Xpert Xpress SARS-CoV-2 reverse transcription-PCR (RT-PCR) test was used to determine the cycle threshold (CT) value for any specimens that were discrepant between the SOFIA and APTIMA TMA tests. Using a CT value of#35 as a surrogate for SARS-CoV-2 culture positivity, we estimate that the SOFIA test detected 87.2% of symptomatic patients tested#5days from symptom onset who were likely to be culture positive.