Blood test

Hi mummies! FTM here. I am currently going through the private route. However my gynae hasn't offered to take my blood test yet and I'm having my third appt on my 12th week (currently 9w now). I was only told that I will be taking the Nipt on my next appt. Is it important to take a blood test? Can I book a separate appt at a polyclinic for my blood test? Do advise. Thanks!