Quad screen

Quad Screen

The Quad Screen (also known as the quadruple marker test, quadruple test, quad marker, or simply quad) is a prenatal screening test that is done during pregnancy to determine the risk of the baby having certain chromosomal abnormalities. These include Down syndrome, Trisomy 18, and neural tube defects such as spina bifida and anencephaly.

Procedure

The quad screen is typically performed between the 15th and 20th weeks of pregnancy. It involves taking a sample of the mother's blood and measuring the levels of four specific substances: Alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), unconjugated estriol (uE3), and Inhibin A. These substances are produced by the baby and the placenta, and their levels can indicate whether the baby is at risk for certain conditions.

Interpretation

The results of the quad screen are combined with the mother's age and other factors to calculate the risk of the baby having certain conditions. It's important to note that the quad screen is a screening test, not a diagnostic test. This means it can indicate a higher risk of a condition, but it cannot definitively diagnose a condition. If the quad screen results indicate a higher risk, further diagnostic tests such as amniocentesis or chorionic villus sampling may be recommended.

Limitations

While the quad screen can provide valuable information, it has limitations. It does not detect all cases of the conditions it screens for, and it can sometimes give false-positive or false-negative results. It also does not screen for all types of birth defects or genetic disorders. Therefore, it's important for expectant parents to discuss the benefits and limitations of the quad screen with their healthcare provider.

See also

• Prenatal testing
• Genetic counseling
• Birth defect
• Genetic disorder

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