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Alpha-Fetoprotein (AFP), Amniotic Fluid — Multiples of Median (MoM)

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

Amniotic fluid AFP is measured after amniocentesis and reported relative to the median level for gestational age to help assess certain fetal abnormalities.

Quick summary

["This result helps evaluate the risk of some fetal birth defects, but it must be interpreted with ultrasound and other prenatal findings."]

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

Key facts at a glance

LOINC
29595-6
Short code
AFP MoM Amn
Synonyms
AFP 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 alpha-fetoprotein (AFP) in amniotic fluid, the fluid surrounding the fetus. The result is reported as multiples of the median (MoM), comparing the measured level with the typical AFP level for the current gestational age.

Why might I need this test?

Amniotic fluid AFP may be used as part of prenatal evaluation, especially if ultrasound suggests a possible neural tube defect or certain other fetal abnormality. It is interpreted together with ultrasound, pregnancy history, and other laboratory results rather than as a stand-alone diagnosis.

How is the test performed?

Amniotic fluid is collected during an amniocentesis procedure. A laboratory measures AFP in the sample and adjusts the result for gestational age, reporting it as multiples of the median.

How do I prepare for the test?

The AFP measurement itself requires no special preparation, but it is usually obtained during amniocentesis. Follow your obstetric clinician's instructions before and after the procedure, including guidance about activity, fluid intake, warning symptoms, and any follow-up testing.

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 (MoM)

Frequently asked questions

What does MoM mean?
MoM means multiples of the median. It shows how the AFP result compares with the typical AFP level for the same gestational age, with 1.0 MoM representing the median.
Does an elevated AFP MoM confirm a birth defect?
No. An elevated result can raise concern for certain abnormalities, but it must be interpreted with ultrasound and other prenatal assessments.
How is the amniotic fluid sample obtained?
A clinician usually collects the sample during amniocentesis using a needle placed through the abdomen into the amniotic sac under ultrasound guidance.
  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