In a Quad screen for Trisomy 21, which of the following is true?

The quad screen is a maternal serum screening test used to assess the risk of certain chromosomal conditions in the fetus, including Trisomy 21 (Down syndrome). In the context of Trisomy 21, certain marker levels are typically altered, which helps in identifying the risk.

For Trisomy 21, the correct findings in the quad screen would show that alpha-fetoprotein (AFP) levels are low, indicating a decreased production of this protein by the fetus. Estriol (E3) is also usually found to be low, as the placental function may be affected, leading to lower estriol production. Human chorionic gonadotropin (HCG) is elevated in this condition, as it is produced at higher levels by the placenta in response to the abnormal development characteristics associated with Down syndrome. Additionally, inhibin A, which is another marker produced by the placenta, is also elevated in cases of Trisomy 21, further aiding in distinguishing this condition from other anomalies.

Thus, the profile indicating that AFP is low, E3 is low, HCG is high, and inhibin A is high provides a reliable assessment that aligns with the typical hormonal changes associated with Trisomy 21 in quad screening