Blood test to find out the sex ?

Elise • Hi my name is Elise and I'm 27, my husband and I got married in May and are expecting our 1st baby together. I have a 4yr old daughter from a past relationship . We are stationed in Hawaii :)
How many people here have had this blood test done and how accurate are the results ? Has anyone been told they were having a girl via the blood test and ended up with a boy or vice versa? I just wanna know the stats before looking into it . Thanks