Inconclusive NIPT... help!!

Catherine
I had the NIPT cell free DNA test last week when I was about 10 weeks pregnant. Results came back today inconclusive. They need about 2.8% of the DNA mixed with my blood and I only had about 1.7%. I'll go back next week for an ultrasound and another NIPT. Hopefully the numbers increase. I'm just hoping this isn't indicative of a problem. I had a miscarriage at 6 weeks and a chemical pregnancy prior to this. I'm 31. I've already had two ultrasounds and everything was healthy. Has anyone else had an inconclusive NIPT? Waiting a week will be nerve wracking.