Sequential Screening Tests

I decided to have some genetic testing done with this pregnancy simply due to my age. At 32, I'm not high-risk yet, but I still worry about the possibility of Down's Syndrome, so I decided to have some screening done, which involves an ultrasound and bloodwork. I'm the type of person that would rather know about a huge health issue, such as Down's; I would hate to be surprised with the news at the hospital!

A couple of weeks ago, I had the US and blood draw, and the good news is, I just have to go back for another draw. As it explains below, if I the tests showed there was a risk (above 4%), my Dr. would recommend a more high risk procedure or genetic counseling instead. Although there are no guarantees, this screening does recognize many cases, as shown by the stats below, so the fact that I just have to have the 2nd trimester blood draw is great. Another reassuring factor occurred during the US when the technician told me the nuchal space (the fluid at the back of the baby's neck) was 1.5 mm, and a good "average" range is between 1-2.4 mm. Anything over 2.4 means there's an elevated risk, and anything over 3 means there is DEFINITELY something wrong. He said 1.5 was a great number, and that he wouldn't worry about it.

Sequential Screening is a variation of integrated screening. With this test a preliminary result for Down syndrome is available about 1 week after the first blood draw and ultrasound. The preliminary result determines if the risk for Down syndrome is higher or lower than 4%. When the result is lower than 4%, the second blood draw is performed at 15-22 weeks and a final result is available approximately 1 week later. When the result is higher than 4%, a woman may choose skip the second blood draw and have a CVS or amniocentesis instead.

Do the screening tests find all babies with a chromosome abnormality or spina bifida?

Integrated and sequential screening finds about 90% of Down syndrome, 90% of open spine defects, and about 60% of trisomy 18 pregnancies.