Why the test is done:
This test is done to help provide a screening for Neural Tube Defects (NTD) like spina bifida, anenecephaly, etc. It has more recently tried to predict the risks of Downs Syndrome.
The most frequent reasons for its use are:
- Screening for certain genetic defects or anomalies
- Assist in certain genetic testing procedures like Amniocentesis and CVS
How the test is done:
It is a blood test from the mother. It can be drawn either in a lab, hospital or in the office of your practitioner.
When the test is done:
This test is most sensitive between 15 and 17 weeks of gestation. Accurate dating and assurance of the number of babies is very important. Both of these factors can through the results off.
How the results are given:
Test results are usually given in percentages. Examples: Risk of Neural Tube Defect 1 in 500
Risks involved:
There is no risk to the test itself. However, due to the risk of a false positive (meaning baby is said to have a problem but is in fact helathy), this test often leads to other more invasive tests that do carry risk to the pregnancy and baby. These are often used:
- Ultrasound (Level II)
- Amniocentesis
Alternatives:
Ultrasound screening can also help determine this status with a bit less accuracy. More invasive tests can be used as mentioned above.
Where do you go from here?
Dependent on results.
Other Similar Tests
Some also perform similar tests known as the Penta Screen, Quad Screen, Triple Screen, MSAFP, etc.
Other Resources:
