Is there something else I can do besides an amnio?

I have just had my 19 week ultrasound with two indicators of DS...also had a triple screen blood test before showing "normal". I don't want an amnio, so IS there any other tests I can have that will help indicate the probability a little better? Just so I can know? I will have my son regardless of DS or not, but it would be nice to know. I won't have the amnio due to the small risk of miscarriage.