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Fetal Protein Screening (Quad Screen) – Serum Alpha-Fetoprotein (AFP), Pregnancy-Associated Plasma Protein-A (PAPP-A), Estriol, and Human Chorionic Gonadotropin (hCG)

Published: August 9, 2026Updated: August 16, 2026

This blood test checks levels of four key proteins in your blood to help assess your baby’s health and detect certain birth defects or chromosomal conditions.

Quick summary

["The Quad Screen helps identify risks early for conditions like Down syndrome or neural tube defects."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
11875-2
Short code
Fet positn US
Synonyms
Fet positn US
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
us
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What the Test Measures

Your healthcare provider will draw blood from a vein in your arm. The test measures four proteins produced by your baby and placenta: Alpha-fetoprotein (AFP), Pregnancy-Associated Plasma Protein-A (PAPP-A), Estriol, and Human Chorionic Gonadotropin (hCG). These levels vary depending on your pregnancy stage and health.

Why It’s Done

The Quad Screen is typically done between 15 and 22 weeks of pregnancy to screen for genetic or structural abnormalities. It’s often part of your first prenatal visit or a follow-up check.

How the Results Are Used

Results help determine if your baby is at higher risk for conditions like Down syndrome, spina bifida, or other chromosomal issues. Your provider will discuss next steps, such as additional testing or monitoring.

What to Expect Before or After

You may need to fast for 8–12 hours before the test, but this depends on your provider’s instructions. Afterward, you’ll likely have mild bruising or soreness at the needle site, which goes away quickly.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Quad Screen

Frequently asked questions

When will I get my results?
Results are usually available within 1–3 business days. Your provider will explain them in detail during a follow-up visit, including any recommended next steps.
What does a ‘normal’ result mean?
A ‘normal’ result means your protein levels are within expected ranges for your pregnancy stage, but it doesn’t guarantee your baby is completely healthy. Further testing may still be recommended.
Can I eat or drink before the test?
Check with your provider first, as fasting may be required for accuracy. Some labs recommend light snacks, but avoid heavy meals or alcohol.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy