Dual marker is a prenatal test that offers early information about a baby’s risk of certain chromosomal conditions, specifically, Down syndrome (trisomy 21) and extra sequences of chromosome 18 (trisomy 18).
Dual marker also called First trimester screening, has two steps:
• A blood test to measure levels of two pregnancy-specific substances in
the mother’s blood — pregnancy-associated plasma protein-A
(PAPP-A) and human chorionic gonadotropin (HCG)
• An ultrasound exam to measure the size of the clear space in the tissue at the back of the baby’s neck (nuchal translucency)
Typically, first trimester screening is done between 9th and 14 th weeks of pregnancy.
• SPECIMEN REQUIRED: Serum
• Collection Container/Tube:
• Preferred: Serum gel
• Acceptable: Red top