MarkY is correct - an antigen is something that will provoke an immune system response, an antibody is the response. The easy way to know what you're getting is that an antibody test involves drawing blood. Vaccination does cause your body to begin producing antibodies without the actual presence of the virus; a positive antibody test could mean either you've been vaccinated or that you have had (and may well have recovered from) the virus.

https://www.fda.gov/consumers/consum...testing-basics