Alpha-Fetoprotein (AFP), Unadjusted, Maternal Serum/Plasma
Measures AFP in maternal serum or plasma. During pregnancy, it may be used with other screening tests to assess the risk of certain fetal conditions.
["An abnormal maternal AFP result may affect prenatal screening risk estimates, but it cannot diagnose a fetal condition by itself."]
Key facts at a glance
- LOINC
- 23812-1
- Short code
- AFP unadj MoM SerPl
- Synonyms
- AFP unadj MoM SerPl
- Category
- liver
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0
- Ref high
- 10
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 82105
- SNOMED
- 394971007
- 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 made by the developing fetus. This blood test measures AFP in maternal serum or plasma when used for prenatal screening.
Why might I need this test?
Maternal AFP may be part of screening for open neural tube defects and certain chromosomal conditions, such as Down syndrome. It is usually interpreted with other prenatal screening results, medical history, and ultrasound rather than as a stand-alone test.
How is the test performed?
A blood sample is drawn from a vein and separated into serum or plasma. A laboratory instrument then measures the AFP concentration, commonly using an immunoassay.
How do I prepare for the test?
Fasting is usually not required. If the test is part of prenatal screening, follow your clinician's instructions because the recommended timing and interpretation depend on gestational age and other screening results.
Reference range
Normal: <10 ng/mLN/A
No special preparation required. For PSA, avoid sexual activity for 24-48 hours before the test.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
During pregnancy, a higher-than-expected AFP level may be associated with open neural tube defects, multiple gestation, or some other fetal or placental circumstances. A lower-than-expected level may be associated with certain chromosomal conditions, including Down syndrome. An abnormal result requires clinical interpretation and may lead to additional testing, but it does not confirm a diagnosis.
Short name
Maternal Serum AFP
Frequently asked questions
Does an abnormal AFP result mean my baby has a condition?
Do I need to fast before this test?
Why might the AFP test need to be repeated?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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