positive blood test

[mariaraceli]

Iam 16 weeks pregnant and I received a call this morning from my doctor
That the blood test that detects down syndrome was positive !
The doctor wants me to get another test done but iam really scare don't know
If I should ?

[Rrrrrachel]

There is no blood test that detects Down syndrome. There is a blood test that, combined with an ultrasound, can help assess your babies risk of Down syndrome. I think the benchmark is something like if your risk is lower than an average 35 year old it's negative and if it's higher it's positive. It is not a yes or no test, it just tells you if your risk is elevated. The only way to know for sure is to do an amnio, which of course is risky. There are also some other non conclusive tests that can help you further assess your risk. I suggest you consider what you would do if your child for sure had downs. If it wouldn't impact your plans for the pregnancy you may want to skip further testing.

[phathui5]

The maternal blood screen for Down's doesn't test to see if baby has Down syndrome. It is a screening to identify moms who have a higher chance of carrying a baby with Down syndrome.

You don't have to get any more testing if you don't want to, especially if you would be ok with raising a child with Down's. It's mainly a CYA on your doctor's part.

And since this is MDC, I'm going to take this opportunity to point out that, if you have midwives in your area, you might get better prenatal care if you were seeing a midwife. We take the time to explain the tests to our clients and what the results mean.

[Kate&Joey]

There actually are two blood tests to evaluate the possibility of DS, as well as other chromosomal issues.  The first, or screening, test gives you a ratio (like Rrrrachel mentioned) based on your age.  For example, the average risk of DS in a woman my age is 1 in 35.  The result of my blood test put me at 1 in 18, or an elevated risk.

But I was able to do a second, more diagnostic, blood test.  This determined with a 99% accuracy, that the baby does not have DS. 

I wonder if this is a new test that isn't offered widely because I don't think I've seen it mentioned here on MDC.