I can’t get my DR to perform an antibody test. Was this a personal doctor that did it? Did you have to request the test?
The local Gerbes (owned by Kroger) pharmacy does it.
It cost $25.
I found it by doing this search for my town.
https://duckduckgo.com/?q=covid+antibody+testing+&ia=web
Plug in your town and see what comes up.
You can get tested on your own. Plenty of labs allow you to "book" a test with them directly.
Also, maybe you need a new doctor.
Give blood. They’ll check it for you.
They have to allow you that test. Go to Kroger to get it as someone posted upthread.