Waiting for Harmony test results

Hi all ! I'm 38, pregnant with my second and 13w5d. I had my nt scan a week ago and the measures where all in the normal range. This monday, the lab called for my blood test results... my risks are 1/171, which is considered high risk. My last pregnancy, at 35, I was 1/500. I was expecting to have similar results, not a so much higher risk...

Anyways I'm a bit concerned, although the lab told me this was the normal risk for my age. So I went to have my harmony test done, and now I'm waiting for the results... might take up to 10 working days. The wait is killing me !!!

What tests did you guys have done and what were your results ?

Is it possible to get a positive for trisomy when nuchal scan was normal ?? I'm guessing it must be rare...