Blood test before first ob appointment?

Nina

Hi is it necessary to get a blood test for Hcg, progesterone etc after BFP? My first OB appointment is not until 8 weeks, I’m 3.5weeks now. My pcp said they only do urine test but not blood confirmation. I heard low progesterone can be found by blood test early. Just really wonder what we can do in this 4-5 week wait 😂