Skip to content

Alpha-Fetoprotein, Amniotic Fluid

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

Measures alpha-fetoprotein (AFP) in amniotic fluid during prenatal evaluation, usually after amniocentesis, to help assess certain fetal abnormalities.

Quick summary

["Amniotic fluid AFP is a specialized prenatal test used to help evaluate fetal conditions such as open neural tube defects."]

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

Key facts at a glance

LOINC
29253-2
Short code
AFP adj MoM Amn
Synonyms
AFP adj MoM Amn
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?

This test measures the amount of alpha-fetoprotein (AFP), a protein made by the developing fetus, in the fluid surrounding the fetus.

Why might I need this test?

Amniotic fluid AFP may be used as part of the evaluation for certain birth defects, especially open neural tube defects and some abdominal wall abnormalities. It is generally considered alongside ultrasound findings, genetic tests, and other prenatal information.

How is the test performed?

A clinician obtains amniotic fluid through a procedure called amniocentesis. The laboratory then measures AFP in the collected sample.

How do I prepare for the test?

Amniotic fluid AFP is not collected with a routine blood draw, so there are no usual food or fasting instructions for the AFP measurement itself. Follow your clinician's directions for amniocentesis, including which medications to take or temporarily avoid.

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.

A higher-than-expected AFP level in amniotic fluid may be associated with open neural tube defects or certain other fetal abnormalities. Results can also be affected by factors such as fetal blood in the sample, pregnancy complications, or multiple gestation. Because of these influences, the result should be interpreted by your prenatal care team together with ultrasound and other testing.

Short name

Amniotic fluid AFP

Frequently asked questions

Is this the same as the routine maternal blood AFP test?
No. Routine prenatal AFP screening uses a blood sample from the pregnant patient, while this test measures AFP in amniotic fluid collected by amniocentesis.
Does an abnormal result mean the fetus definitely has a birth defect?
No. An abnormal result indicates that further evaluation may be needed, but it does not by itself confirm a birth defect. Other prenatal findings are considered when interpreting the result.
Can this test be performed without amniocentesis?
No. Amniotic fluid must be collected through amniocentesis before the laboratory can measure AFP in it.
  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