How long would it take for antibodies to show up in an antibody test after infection with covid 19? TIA.

Somewhere between 7 and 14 days

My doctor told me at least 3 weeks after infection, that was over a year ago so something may have changed since then.

Well the truth is that different people may mount an antibody response in different timeframes and the various tests have different thresholds for positivity. This is one reason antibody tests are not used to diagnose acute infection.

For most people antibody response will peak around 3 weeks but will turn positive between 7 and 14 days.

Reportedly IgM and IgG show up about the same time for COVID-19 but IgG hangs around much longer.

IgM will be positive before IgG. 3 weeks is probably early safe window.

This is interesting. I thought the body made antibodies right away as it combats a virus. Is that the case it just takes longer to reach a detectable level?

It takes the immune system a while to start cranking out antibodies to a new antigen/virus. It is much faster on subsequent exposures.

Thanks for the info.