it is better to have employees get the regular, NOT the rapid test if at all possible, and here is why:
There is a big difference in the accuracy of the rapid tests vs. the PCR (polymerase chain reaction) lab test. The reason the rapid tests have a lower accuracy rate than the PCR test is because the viral load has to be at its peak to clearly register positive on the rapid test. The regular PCR test will detect COVID-19 in the nasal passages at nearly all phases of the virus. So, if someone has just become infected, or is at the end of their infection, the viral load may be so low as to not register on the rapid test but would register on the PCR test.
I have attached a graph from the UC Davis Health System that shows the arc of the viral RNA to give it context. The other lines are the antigens that are detected in the antibodies test (which is different from the testing done for the active virus).