Which markers are assessed in the quad screen during prenatal screening?

Which markers are assessed in the quad screen during prenatal screening?

• A. MSAFP (maternal serum alpha-fetoprotein), hCG, estriol, and inhibin A
• B. AFP, insulin, hCG, and progesterone
• C. MSAFP, TSH, glucose, and cortisol
• D. Alpha-fetoprotein alone

Answer: (A)

The quad screen is a second‑trimester maternal serum test that uses four specific markers to estimate the risk of fetal neural tube defects and chromosomal abnormalities such as Down syndrome. The four markers are maternal serum alpha-fetoprotein (MSAFP), human chorionic gonadotropin (hCG), unconjugated estriol, and inhibin A. MSAFP is typically elevated with open neural tube defects and certain ventral wall defects, while levels tend to be lower with chromosomal abnormalities. hCG tends to be elevated in pregnancies with Down syndrome and other trisomies. Estriol is usually decreased in Down syndrome, and inhibin A is often increased in Down syndrome. These patterns help clinicians assess risk and decide whether further diagnostic testing (like targeted ultrasound or invasive testing such as amniocentesis with karyotype) is warranted. Other markers listed in the other options (insulin, progesterone, TSH, glucose, cortisol) are not part of the quad screen, and measuring alpha-fetoprotein alone does not constitute the quad screen.

The quad screen is a second‑trimester maternal serum test that uses four specific markers to estimate the risk of fetal neural tube defects and chromosomal abnormalities such as Down syndrome. The four markers are maternal serum alpha-fetoprotein (MSAFP), human chorionic gonadotropin (hCG), unconjugated estriol, and inhibin A.

MSAFP is typically elevated with open neural tube defects and certain ventral wall defects, while levels tend to be lower with chromosomal abnormalities. hCG tends to be elevated in pregnancies with Down syndrome and other trisomies. Estriol is usually decreased in Down syndrome, and inhibin A is often increased in Down syndrome.

These patterns help clinicians assess risk and decide whether further diagnostic testing (like targeted ultrasound or invasive testing such as amniocentesis with karyotype) is warranted. Other markers listed in the other options (insulin, progesterone, TSH, glucose, cortisol) are not part of the quad screen, and measuring alpha-fetoprotein alone does not constitute the quad screen.