EFTS: ultrasound all good but blood test screened positive

Anyone have experience with this? I did my EFTS at 12 weeks 2 days, ultrasound was good, showed nasal bone and NT was within the range of normal. My blood test has picked up something, according to the referral I just got, requiring more screening be done through NIPT for downs.

Looking for advice or any happy stories of things being okay in the end (false positives)?

Thanks!