Amniotic Fluid Alpha-Fetoprotein (AFP) Mass Concentration
This test measures the amount of alpha-fetoprotein (AFP), a protein produced by the fetus, in amniotic fluid. It helps assess fetal development and screen for certain birth defects.
["AFP in amniotic fluid can indicate risks for neural tube defects or chromosomal abnormalities."]
Key facts at a glance
- LOINC
- 11860-4
- Short code
- Fet Cisterna magna Diam US.meas
- Synonyms
- Fet Cisterna magna Diam US.meas
- 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-measured
- 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 AFP in Amniotic Fluid Used For?
AFP testing in amniotic fluid is primarily part of a prenatal screening test. It helps identify potential issues like spina bifida (an open spinal cord defect) or other neural tube defects. It may also be used in conjunction with other tests to evaluate chromosomal conditions, such as Down syndrome.
How Is the Test Performed?
Amniotic fluid is collected through a procedure called an amniocentesis, where a small amount of fluid is taken from around the fetus. The fluid is then analyzed in a lab to measure AFP levels. This test is typically performed between 15 and 20 weeks of pregnancy.
What Are Common Results and Next Steps?
Results are usually reported as a mass concentration value. If the AFP level is elevated, it may signal an increased risk for certain birth defects, prompting further diagnostic testing. If the level is low, it may raise concerns about other conditions that require additional evaluation.
What Does a Low or High AFP Level Mean?
Elevated AFP levels in amniotic fluid can sometimes indicate neural tube defects, though they are not definitive on their own. Low levels may be associated with other conditions, such as certain chromosomal abnormalities or multiple gestation (e.g., twins). Always discuss results with your healthcare provider.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: AFP in Amniotic Fluid Plays a Key Role in Prenatal Screening by Identifying Potential Genetic or Structural Birth Defects Early. While not a definitive diagnostic test, it helps guide further evaluation, such as additional genetic testing or ultrasounds, to ensure the health and safety of the pregnancy.
Short name
AFP Level in Amniotic Fluid
Frequently asked questions
Why is AFP Testing Done During Pregnancy?
How Often Is This Test Performed?
Can AFP Levels Change Over Time During Pregnancy?
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.
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Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy