Blood work question!

Ladies, congrats to all of you preggo mommys! I have had 3 days of positives (4 tests total), and unless something changes I am going with BFP! It hasn't quite hit me lol. Well....hubby and I are going to my family dr friday to have blood work drawn to confirm. Will they know that day If I am pregnant?? I know someone said they will require me to come back possibly next week so  they can check my numbers. Just want to go Friday and find out friday