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Alpha-Fetoprotein (AFP), Amniotic Fluid — Interpretation

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

Measures alpha-fetoprotein in amniotic fluid to help evaluate certain fetal abnormalities, usually alongside ultrasound and other prenatal screening tests.

Quick summary

["Amniotic fluid AFP is one part of prenatal assessment and should be interpreted together with your other pregnancy screening results."]

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

Key facts at a glance

LOINC
41273-4
Short code
AFP Interp Amn-Imp
Synonyms
AFP Interp Amn-Imp
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
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 (AFP) is a protein produced during fetal development. This test measures AFP in amniotic fluid, the fluid surrounding the fetus, to help assess the risk of certain birth defects.

Why might I need this test?

It may be used when a prenatal screening result, ultrasound finding, or family history suggests possible fetal abnormalities. Results are considered along with gestational age, ultrasound findings, maternal blood screening, and other clinical information.

How is the test performed?

Amniotic fluid is usually collected during a clinician-performed procedure called amniocentesis. A laboratory then measures the AFP level in the sample, and the result is interpreted by your prenatal care team.

How do I prepare for the test?

Fasting is generally not required for the AFP measurement itself. Because amniotic fluid must be collected by a clinician, follow the specific instructions provided before or after the amniocentesis procedure.

Reference range

Normal: <10 ng/mLN/A

Specimen: fluid

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.

◆Associated findings1

Short name

Amniotic fluid AFP

Frequently asked questions

What does alpha-fetoprotein measure?
AFP is a protein made by the developing fetus. Its level in amniotic fluid can provide information about certain fetal abnormalities.
Does an abnormal AFP result mean the fetus has a birth defect?
No. An abnormal result is not diagnostic by itself and must be interpreted with ultrasound, gestational age, and other screening or diagnostic test results.
Is this the same as the AFP test in maternal blood?
No. Amniotic fluid AFP and maternal serum AFP use different samples and are interpreted in different ways, although both may be part of prenatal assessment.
  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