hiv is scary. but unfortunately nothing in life is 100% but i can tell you that hiv cannot live outside the body for long at all at the very longest 2 minutes and that's a generous estimate. there are no cases of someone catching hiv in the way you described and especially in a general testing site where the vast majority of people who test come back negative - so in that respect even if there was any blood on the counter its likely from hiv negative blood.
my hiv test came back negative. a positive-test person was in the room before me. could i have been exposed to hiv? . i touched the countertop doorknob of the room etc.