What does the quad screen test primarily screen for?

The quad screen test is a blood test performed during the second trimester of pregnancy, typically around 15 to 20 weeks of gestation. It evaluates levels of four specific substances in the mother’s blood to assess the risk of certain genetic conditions in the developing fetus. The primary conditions screened by the quad screen are trisomy 21 (Down syndrome) and trisomy 18 (Edwards syndrome).

When interpreting the results, elevated levels of markers associated with Down syndrome can indicate an increased risk for the condition, while decreased levels might signal an elevated risk for trisomy 18. This test does not directly diagnose these conditions but rather provides risk estimates that further genetic counseling or testing may be considered based on the findings.

The other options do not pertain to the primary focus of the quad screen. Gestational diabetes is assessed through glucose tolerance testing rather than a quad screen. Preeclampsia involves monitoring blood pressure and urine for protein, not through the quad screen test, which does not evaluate hypertensive disorders. Fetal growth restriction is typically assessed through ultrasound and fetal monitoring rather than through blood markers evaluated in the quad screen.