_Performance of Rapid Antigen Tests for SARS-CoV-2
It is important for clinicians and testing personnel to understand the performance characteristics, including sensitivity and specificity, of the particular rapid antigen test being used, and to follow the manufacturer’s instructions and package insert.
The “gold standard” for clinical diagnostic detection of SARS-CoV-2 remains RT-PCR. Thus, it may be necessary to confirm a rapid antigen test result with a nucleic acid test, especially if the result of the antigen test is inconsistent with the clinical context. When confirming an antigen test result with a RT-PCR test, it is important that the time interval between the two sample collections is less than two days, and there have not been any opportunities for new exposures between the two tests. If more than two days separates the two tests, or there have been opportunities for new exposures between the two tests, the nucleic acid test should be considered a separate test – not a confirmatory test. Table 2 summarizes the differences between RT-PCR tests and antigen tests.