Blood Test

Hi all. I need to get a full blood test tomorrow checking for everything. I had a blood test to confirm my pregnancy and HCG came back 2800 and they told me I’m 4-5 weeks pregnant. By my first day of last period that would put me at 4 week and 6 days. It says on the form that I need to fast for my blood test. They didn’t tell me so I don’t know how long to fast for. What do you all think?