Pregnant woman doing exercise

First and second trimester serum screening

Serum Screening

Maternal serum screening tests use a blood sample from the mother to identify pregnancies at risk for certain birth defects

supporting image

What’s the difference between serum screening and noninvasive prenatal testing?

While serum screening has been in use for more than 40 years, noninvasive prenatal testing (NIPT) was introduced in 2011 (with our own test, MaterniT 21, being the first commercially available NIPT). Both tests are noninvasive (i.e. they require a blood sample from the mother’s arm, not tissue from the placenta or fluid from the amniotic sac).

However, serum screening typically screens for just three common birth defects—Down syndrome, trisomy 18 and open neural tube defects—whereas NIPT can screen for many more defects, as well as fetal sex. Additionally, MaterniT 21 PLUS has higher detection rates than serum screening.

A maternal serum screening test:

  • tells you the chance that your baby could have trisomy 21 (Down syndrome), trisomy 18 or open neural tube defects
  • will detect about 80%–90% of babies with these birth defects, depending on the particular test your doctor uses and how far along you are in your pregnancy. That means that about 10%–20% of these birth defects are missed by this screening
  • sometimes shows an increased risk even when the baby does not have one of these problems
  • does not cause miscarriages

At Labcorp, We Offer Five Choices in Serum Screening.

Additional Resources