This is how a (proof of antibody) document from a Swedish doctor looks.
I was sick a couple of weeks ago and the day before yesterday I did the antibody test and it was positiv. (I have antibody)
This is how the paper looks.
I have antibodies for the Coronavirus SARS-CoV-19
Tengo anticuerpos para Coronavirus SARS-CoV-19
Jag har antikroppar mot Coronavirus SARS-CoV-19