Model for Interpreting Discordant SARS-CoV-2 Diagnostic Test Results

Abstract

We devised a model to interpret discordant SARS-CoV-2 test results. We estimate that, during March 2020-May 2022, a patient in the United States who received a positive rapid antigen test result followed by a negative nucleic acid test result had only a 15.4% (95% CI 0.6%-56.7%) chance of being infected.

Keywords: COVID-19; PCR; SARS; SARS-CoV-2; coronavirus; coronavirus disease; diagnostic test; rapid antigen test; respiratory infections; severe acute respiratory syndrome coronavirus 2; viruses; zoonoses.

Figure

Estimated probability that a positive RAT result is erroneous given a subsequent negative NAAT in a model for interpreting discordant SARS-CoV-2 diagnostic test results. A) Estimated RAT false-positive percentages for levels of community transmission ranging from 0­–2,500 COVID-19 cases per 100,000 population. Green and yellow shading correspond to the Centers for Disease Control and Prevention threshold for low and medium or high community levels (8). Line color corresponds to different numbers of days between the initial RAT and confirmatory NAAT, ranging from same day (lightest gray) to 3 days later (black). B) Estimated RAT false-positive percentages for the United States (purple), Florida (green), and New York (orange) during March 2020­–May 2022, assuming the NAAT is administered 1 day after the RAT and that 1 in 4 cases were reported. Shading reflects uncertainty in Centers for Disease Control and Prevention estimated COVID-19 infection underreported, ranging from 1 in 3 to 1 in 5. The gray time series along the bottom indicates the daily 7-day sum of reported COVID-19 cases in the United States. NAAT, nucleic acid amplification test; RAT, rapid antigen test.