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Alpha-Fetoprotein, Amniotic Fluid — Substance Concentration

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

Measures alpha-fetoprotein (AFP) in amniotic fluid to help evaluate certain fetal conditions when prenatal testing is needed.

Quick summary

["An abnormal amniotic fluid AFP result may prompt additional prenatal evaluation but does not by itself establish a diagnosis."]

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

Key facts at a glance

LOINC
15019-3
Short code
AFP Amn-sCnc
Synonyms
AFP Amn-sCnc
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 made by the developing fetus. This test measures its concentration in amniotic fluid, the fluid surrounding the fetus during pregnancy.

Why might I need this test?

Amniotic fluid AFP may be measured when a clinician needs more information about fetal development, particularly if an ultrasound or other prenatal screening suggests a possible abnormality. It is not the same as the routine AFP screening test performed on a pregnant person's blood.

How is the test performed?

A clinician obtains a small sample of amniotic fluid, usually during a procedure called amniocentesis. The laboratory then measures the AFP concentration in that sample using a laboratory assay.

How do I prepare for the test?

No fasting or medication changes are generally required for the AFP measurement itself. Because obtaining the sample may involve amniocentesis, your clinician will explain the procedure, its risks, and any specific preparation instructions before it is performed.

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

Is this the same as the AFP test done on maternal blood?
No. This test measures AFP directly in amniotic fluid, while maternal serum AFP is a blood screening test used for a different purpose.
Does an abnormal AFP result mean the fetus has a serious condition?
No. An abnormal result indicates that further evaluation may be needed, but it does not alone establish a fetal condition or diagnosis.
How is amniotic fluid collected?
A clinician usually collects it with a needle placed into the amniotic sac during amniocentesis under ultrasound guidance. The procedure and its risks should be discussed with the healthcare professional performing 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