Hey Ladies, how early can you have a blood test done to check if you're pregnant?

I thought that I ovulated 6 days before my chart picked up on it (it changed my ovulation date) and I had arranged to have an appt with my dr and have a blood test done but then my chart changed and is telling me im 10dpo (or possibly 11dpo) so should I still go??? furthermore whether to worry about having the blood test or not?

I also want to have a scan done to see if the cyst is gone from my ovary and want to have a general checkup anyway.