The CDC recommends serial testing when performing rapid antigen tests for

COVID-19.

Because there may be a delay between the time a person is exposed
to the virus and the time that virus can be detected by testing, early
testing after exposure at a single time point may miss many infections.
Testing that is repeated at different points in time, also referred to as
serial testing, is more likely to detect infection among close contacts of
a COVID-19 case than testing done at a single point in time.
For a limited time, you can order 2 rapid antigen tests for $129. That is 2 for the price of one.
Serial testing is normally conducted 3 to 7 days apart.
Our rapid antigen test is instrumented, rather than dependent on a technician’s ability to read a
faint line on a test kit.