Sti test

I had unprotected sex and a week and a half later got an sti test. I had sex with the same person a couple of days after the test and am yet to get the results back. If the guy was to have an sti would I have definitely got it the first time? I just would hate to have the test results say that I don't have an sti but end up having one from the second time and not know because the test was done inbetween the two times.