It is only a risk they can give you based on the nuchal thickness and by taking blood on the same day.
I got a call back within a couple of days saying I had a 1 in 9 risk of a cromozone issue, there are three big ones, don't forget it's not only a screening test for downs, also for pascals and Edwards Syndromes in which the outcomes are far worse than for downs. I then had a CVS test, but if your 14 weeks onwards you then can have an amnio to tell 100% accurately if you do have an issue and can get your head round it or look at your options , esp with pascals or edwards.
It was a worrying time, and luckily my baby was fine , but I didn't get out the other side of worry till 17 weeks before we could tell people I was pregnant eg my kids etc , but would have the test again everytime..
I have decided mine was due to the 12 week mmc I had just 6/8 weeks before I got pregnant again as my blood markers showed really high. Do have the convo with your OH, it needs discussing you may have the same views and be worrying for nothing