Kiedy

test is called chorionic villus sampling, {removed} It's very accurate for detecting Downs syn, about 99%. It's advantage over amnio is that it can be done earlier, 10-12 wks, vs 15-22wks depanding on the center. 1 in 23 risk means little unless you tell us your age. As you know risk for Downs increases w/ age, so for me at 28 yrs of age, normal risk is 1:1000, but I tested 1 in 270, and had amnio. So my 1 in 270 may not mean like much of a risk compared to 1 in 23 but for my age it was. They usually offer amnio to all women over 35 b/c risk increases dramatically after that age,
MATERNAL AGE RISK AT BIRTH RISK AT 12 WEEKS
20 1/1527 1/898
25 1/1352 1/795
30 1/895 1/526
32 1/659 1/388
34 1/446 1/262
36 1/280 1/165
38 1/167 1/98
40 1/97 1/57
42 1/55 1/32
44 1/30 1/18

so as you see, it's all relative, the triple screen is only a screen, if it comes up negative, there is no guarentee that your baby would not have Downs, but it would be very unlikely. Hope this helps a bit.