Its technically a test for chromosome abnormalities (e.g., Down's, etc) and I think finding out gender is just a nice bonus. My insurance won't cover it, they told me its considered "experimental" and not medically necessary. Will cost me at least $500 out of pocket.
It's called the harmony test, very accurate, if ur 10 weeks or more they can do it. When they take ur blood for the first round of tests looking for any problems they so it then. Spin ur blood & break down the baby's DNA. Takes about 2 weeks for the results.
The blood test is completely accurate. They specifically find the baby's DNA in your blood to find out the gender.
From what I read it's a requested test and you have to pay like $200 or more for it. It's not covered and not accurate. Better to wait for the ultrasound.