I'm 99% certain that I had COVID in Jan 2020, but I am specifically avoiding getting an antibody test because I don't want it going in my medical file. Now that it is electronic, your insurance company is constantly searching for things like that in their db. It's the same way that I would never admit to the occasional (one or two a month) cigars I smoke, because once "smoker" goes into my medical file, I can never get it out.