I have a positive AFP or triple screen test for Down's Syndrome. What does that mean?
This means that the blood test has determined that your pregnancy has the same risk or higher as that of a 35-year old of being affected by Down's Syndrome. It is not diagnostic. This test is a screening test and is intended to delineate which patients should be offered further testing.
The most common reason for a positive result is the dates of the pregnancy are inaccurate. In this case, ultrasound-directed correction of the dates will typically yield a correct negative result. In the case where the dates are correct, you will be offered counseling and an explanation of the result with a perinatologist. You will be offered a level two ultrasound looking for features seen in Down's syndrome. These are by no means diagnostic. Amniocentesis is the gold standard for diagnosis. This involves placing a needle into the uterus under ultrasound guidance and withdrawing amniotic fluid which can then be tested.