Can I get a blood test already?

JJW
Hi ladies! Happy Friday :) I have a doctors appointment today to check out a calcium deposit on my foot (sorry, TMI) so I figured I would get a blood test done as well since I'm already there. Is it too early for that to even come back positive? I think I ovulated on Saturday because I took a OPK and it came back positive on Friday. Any help or advice would be greatly appreciated. Thank you!