Hunh?? You can't tell if you're pregnant an hour after sex. If you thouhgt you were pregnant from before that and missed a period then no having sex would not mess with the test.

If you asking if you have sex and get pregnant that time, and then take a test...U probably won't get a result. If you're already pregnant and then randdomly have sex again and then test, it shouldn't screw it up.

But you have to a few weeks usually acfter conceiving to get positive test...You might have sex one say, have the spermies floating around you and not have them meet up with an egg until the next day...So you might have to wait longer than you think...

Does this answer you question? I know that this probably doesn't make perfect sense, i'm horrible at puting whats in my head into words.......