I did the antibody covid test and got 0,08 of lgg. its negative because its says to be positive it needs to be +1. but what do those 0,08 mean? why not 0,00?

My sense is that the covid antibody test may react very weakly with other antigens also. I would like an immunologist to answer your question though.

Don’t know which specific antibody test you got (there are several) but a low level of antibody mean that you were probably previously infected with a non-pandemic strain of coronavirus (there are many). Most importantly, you are NOT protected from the pandemic COVID19 strain. Get vaccinated