MomTalk.com August 30, 2008: The women's magazine for moms about children, family, health, home, fashion, careers, marriage & more

What is the Multiple Marker Test?

Between the 15th and 20th weeks of pregnancy, expectant mothers typically are offered a blood test called the multiple marker test. It can sometimes be called a triple screen or a quad screen, depending on the number of things measured.

For the screening, a sample of blood is drawn from the mother to measure the levels of hCG (human chorionic gonadotropin) and estriol, which are produced by the placenta, and alpha-fetoprotein (AFP), which is produced by the fetus. Sometimes the level of inhibin-A, which is made by the placenta, also is measured. The levels of these substances can help doctors identify a fetus at risk for certain birth defects, including neural tube defects (like spina bifida) and chromosomal abnormalities (like Down syndrome).

In determining the results of the test, doctors take into account:

* the mother's age, weight, and ethnicity
* whether she has diabetes
* if she is having twins or other multiples
* the gestational age of the fetus

Many of these factors affect the levels of the substances being measured and the interpretation of the test results, so the accuracy of this information is vital. If any of the information is inaccurate, the results from the screening may be as well. Jump to full text of this article here.