Quad Screen
A maternal serum screening test measuring four biochemical markers to assess risk for chromosomal abnormalities.
Full Definition
The quad screen, also known as the quadruple marker screen, is a second-trimester maternal serum screening test typically performed between 15-20 weeks of gestation. This test measures four maternal serum analytes: alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), unconjugated estriol (uE3), and inhibin A. The results are combined with maternal age and other factors to calculate risk estimates for Down syndrome, Edwards syndrome (trisomy 18), and neural tube defects. While not diagnostic, abnormal results indicate the need for genetic counseling and consideration of definitive testing through amniocentesis.
Usage
Usage note: Hyphenate when used as an adjective; may be written as two words when used as a noun.
In Context
- "The quad screen results showed an elevated risk for Down syndrome requiring genetic counseling." — Laboratory report interpretation
- "Normal quad screen values provided reassurance regarding chromosomal risk." — Prenatal counseling documentation