Alpha-Fetoprotein, Amniotic Fluid — Immunoassay, Mass Concentration
Measures alpha-fetoprotein in amniotic fluid to help evaluate certain fetal abnormalities, including neural tube defects and some chromosomal conditions.
["This test measures AFP in amniotic fluid; abnormal results may suggest a fetal condition but require confirmation."]
Key facts at a glance
- LOINC
- 83075-2
- Short code
- AFP Amn IA-mCnc
- Synonyms
- AFP Amn IA-mCnc
- Category
- liver
- Sample
- fluid
- Container
- Sterile tube
- Units
- N/A
- Ref low
- 0
- Ref high
- 10
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- ia
- CPT
- 82105
- SNOMED
- 394971007
- Specimen volume
- 2-5 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h
- Hemolysis max
- 300
- TAT
- 4–24 hours
- Order
- routine
What is this test?
Alpha-fetoprotein, or AFP, is a protein made by the developing fetus. This test measures the amount of AFP in amniotic fluid, the protective fluid surrounding the fetus.
Why might I need this test?
It may be ordered when prenatal screening suggests a possible neural tube defect or chromosomal condition, or when a clinician wants more detailed information about a pregnancy. It is generally used as an additional evaluation rather than as a stand-alone diagnosis.
How is the test performed?
A clinician obtains a small sample of amniotic fluid, usually during an amniocentesis procedure. A laboratory measures AFP in the fluid using an immunoassay, a method that detects and quantifies the protein.
How do I prepare for the test?
No special food or medication preparation is needed for the AFP measurement itself. The amniotic fluid must be collected by a healthcare professional, so your clinician will explain the procedure, its risks, and any specific instructions.
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.
Higher-than-expected AFP levels may occur with open neural tube defects and some other fetal abnormalities. Lower-than-expected levels can be associated with certain chromosomal conditions, including Down syndrome. Results should be interpreted with the ultrasound findings, gestational age, and other prenatal tests because AFP alone cannot confirm a diagnosis.
Short name
Amniotic fluid AFP
Frequently asked questions
Does an abnormal AFP result mean the fetus has a condition?
How is amniotic fluid obtained?
Is this the same as the maternal serum AFP screening test?
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