Quad Marker Screen
- Sample Type
- Serum
- Fasting
- No
- Unit
- MoM (Multiple of Median)
Function
The Quad Marker Screen is a prenatal blood test performed during the second trimester (usually weeks 15-22). It measures four specific substances in the mother's blood: Alpha-fetoprotein (AFP), Human chorionic gonadotropin (hCG), Unconjugated estriol (uE3), and Inhibin-A. Unlike diagnostic tests, this is a screening tool used to estimate the statistical probability of certain chromosomal abnormalities.
Why it is Ordered
The test is offered to pregnant women to screen for potential fetal health issues without the risks associated with invasive procedures like amniocentesis. It evaluates the risk of:
- Neural Tube Defects: Such as spina bifida or anencephaly.
- Trisomy 21 (Down Syndrome): A chromosomal disorder causing intellectual disability and developmental delays.
- Trisomy 18 (Edwards Syndrome): A more severe chromosomal abnormality.
Associated Conditions
- High AFP: May indicate neural tube defects, multiple pregnancies, or an underestimated gestational age.
- Low AFP, High hCG, Low uE3, High Inhibin: This specific pattern is associated with an increased risk for Down Syndrome.
- Low AFP, Low hCG, Low uE3: This pattern may suggest an increased risk for Trisomy 18.
Check Your Result
Check Your Result
Enter your lab result to see where you stand compared to the standard reference range.
Why Context Matters
The Quad Screen has a high false-positive rate. Factors such as incorrect gestational dating, multiple gestations (twins), maternal weight, and race can significantly skew the results. An abnormal result does not mean the baby has a defect; it simply indicates that further diagnostic testing (like high-resolution ultrasound or amniocentesis) is warranted.
Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.
Clinical References
Source-of-truth databases and clinical guidelines for Quad Marker Screen:
Official Sources
- Medical Care of Adults With Down Syndrome: A Clinical Guideline - PubMedpubmed.ncbi.nlm.nih.gov
Research & Guidelines
- PubMed: Quad Marker Screen Clinical GuidelinesNCBI / PubMed
Related Indicators
Medically Reviewed by Dr. Binoy Babu, MBBS
Board Certified Doctor • 10+ Years Clinical Experience
Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.
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