What exactly is the procedure for the genetic screen testing?

At 12 weeks has anyone had that test done yet?

They just take some blood and check for abnormalities. I don't know exactly how the labs are processed. But it's really just giving blood, like for any other labs.
I also had a Phase2 Ultrasound with mine because my fiance was born with a concave chest and had to have open chest surgery when he was like 8 years old.

You and the baby's father are asked a bunch of questions about your ethnic background and your family history as far as genetic and other illnesses are concerned.

The blood test for this one, thankfully, is just a finger prick, and they squeeze out a few drops of blood onto a test sheet.

The use the results of the blood test, any risk factors in your family history, and the measurements taken from your 12 week ultrasound to determine if your baby is at increased risk for any genetic illnesses. Even if they find increased risk, it doesn't necessarily mean your baby has any problems. It just gives you a guideline as far as choosing if you want to have further (and more invasive) testing done to look for problems.

It's a blood test. There is a protein called alphafetoprotein AFP if its elevated there can be risk for neural tube defects, low side may indicate risk for down syndrome etc... If the blood test is abnormal you will receive a call from the hospital or clinic they will ask you to come as soon as you can for genetic counseling and offer you the option of an amniocentesis.

They take blood and do an ultrasound (they're checking for the thickness of the skull). Doesn't hurt and puts some of your worries to rest.

For Down syndrome - its just an ultrasound where they measured the fuild in the back of the neck.