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Alpha-Fetoprotein (AFP), Serum/Plasma — Substance Concentration

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

A blood test that measures AFP, a protein made by the fetal liver and certain adult tissues. It may be used for prenatal screening or to help evaluate certain liver conditions and tumors.

Quick summary

["AFP results must be interpreted in context because levels vary with pregnancy stage, laboratory methods, and liver health."]

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

Key facts at a glance

LOINC
70180-5
Short code
AAA SerPl Fetus-sCnc
Synonyms
AAA SerPl Fetus-sCnc
Category
liver
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 is this test?

Alpha-fetoprotein, or AFP, is a protein found in the blood. During pregnancy, the developing fetus produces AFP, and the placenta releases some into the mother's bloodstream.

Why might I need this test?

AFP may be measured as part of prenatal screening because the pattern of maternal blood AFP, along with other tests and ultrasound findings, can help assess the risk of certain birth conditions. It may also be measured to evaluate liver disease or when a tumor is being investigated.

How is the test performed?

A blood sample is drawn and sent to a laboratory, where AFP is measured using a laboratory method. The result is usually reported as a concentration in the blood.

How do I prepare for the test?

No special preparation is generally required for a routine serum or plasma AFP test. If the test is part of prenatal screening, your clinician will explain any timing and pregnancy-related considerations.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Alpha-fetoprotein (AFP)

Frequently asked questions

Is this the same as a home pregnancy test?
No. A home pregnancy test detects human chorionic gonadotropin, or hCG, rather than AFP.
Does an abnormal AFP result confirm a birth defect or cancer?
No. An abnormal result indicates that further evaluation may be needed, but it does not confirm a condition by itself. Other laboratory tests, imaging, genetic information, and clinical findings may also be needed.
Can AFP results change during pregnancy?
Yes. AFP levels change as the pregnancy progresses, and factors such as multiple gestation and the timing of the blood draw can affect interpretation. Your prenatal care team will account for these factors.
  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