CMS recently published an Interim Final Rule that would effectively transition the entire industry to PCR testing exclusively. The basis for this decision is that antigen tests do not detect an “active infection”, and therefor cannot accurately detect the coronavirus. Here’s the excerpt taken from CMS’s publication:

“A diagnostic test shows if a patient has an active coronavirus infection. As of the date of this guidance, there are two types of diagnostic tests which detect the active virus – molecular tests, such as RT-PCR tests, that detect the virus’s genetic material, and antigen tests that detect specific proteins on the surface of the virus. An antibody test looks for antibodies that are made by the immune system in response to a threat, such as a specific virus. An antibody test does not identify an active coronavirus infection; therefore, conducting an antibody test on a staff or resident would not meet the requirements under this regulation.”