What is a quad marker screen?
The quad marker screen is a blood test that provides a woman and her health care provider with useful information about her pregnancy. The quad marker screen must be performed between the 15th and 20th weeks of pregnancy. During the quad marker screen, a sample of blood is taken from the woman’s vein. Substances in the blood sample are measured to screen for: • Problems in the development of the fetus’ brain, spinal cord and other neural tissues of the central nervous system (neural tube). Problems with neural tube development can occur as spina bifida or anencephaly (absence of all or part of the brain). Neural tube defects occur in 1 or 2 out of every 1,000 births. The quad marker screen can detect approximately 75 percent of open neural tube defects. • Genetic disorders such as Down syndrome, a chromosomal abnormality. Approximately 1 in 720 babies is born with Down syndrome. The quad marker screen can detect approximately 75 percent of Down syndrome cases in women under age 35 and
