Gender Prediction Kits?

Hey guys
I'm so impatient and I can't wait to find out if it's a boy or girl so I ordered a gender prediction kit. Results will be in today and I'm so excited. I'm fully aware I still need the sex verified by a doctor before I go buy things but has anyone ever used this? If so, was it correct?
For those that don't know what it is.... u send in a blood sample from your finger and they test for male DNA. Of no male DNA then obviously it's a girl and if there is male DNA then it's a boy. The test was very in depth and you have to scrub your hands twice with a scrub brush and sanitize your test area to avoid male contamination. They recommend doing it alone without any males even in your presence. Anyone do this?