With a PCR test?
Lab tests. plural. d diner. ldh. ferritin. liver and kidney functions. c reactive proteins. covid by pcr or antigen whatever is available at the time. It is not just one lab test. covid has a typical clinical history abs presentation as well as pattern of lab abnormalities. this is his any diagnosis is made. I assure you I know what I am treating despite what the armchair practitioners on this thread seem to think.