If i ovulate on sept 2, when is the soonest i can do pregnancy blood test? thank you for the answer

Patience...: Patience is a virtue that all parents and future parents should seek. A urine pregnancy test done correctly should give a reliable result 3 weeks after sex. A blood test is not needed. Hopefully, it will be what you wish it to be, but there should be no need to give it another thought until then. If one's normal regular menstrual period comes, she is not pregnant and a test is not needed.