Chromosomal blood test to find out gender!

Has anyone had this test done? I had it done at my last appt which was a week ago. I'm so anxious to find out the results. Just wondering if your results were correct for you. My ob said that its 99% correct, but this is new to me. I also have an u/s on August 25th too, but once I get these results I may want to go buy a little bit of stuff!