blood testing gender test

Has anyone else had a blood test to determine if baby was sick and also found out baby's gender ? I had one done at 16 weeks found out at the start of this month that I was having a girl and I was told through ultrasound it was a girl also but I wasn't able to get a picture of her parts cause she was moving to much so I have been worried I didn't get to see if she is for sure a girl and my doctor said he will not be doing another ultrasound for me this pregnancy because the gender test he sent in for was 99% accurate . Has anyone had a false gender result from blood work ?