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Serum or plasma concentration of free fatty acids (FFAs) via enzymatic method

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

This test measures the level of free fatty acids in your blood, which are important energy sources for your body. They play a key role in metabolism and can be influenced by diet, exercise, and certain health conditions.

Quick summary

["FFAs help your body use energy efficiently and support normal bodily functions."]

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

Key facts at a glance

LOINC
3238-3
Short code
Fact XIII Ag PPP IA-aCnc
Synonyms
Fact XIII Ag PPP IA-aCnc
Category
chemistry
Sample
plasma
Container
Lavender-top (EDTA) or Green-top (Heparin)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
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

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like unusual fatigue, rapid or irregular heartbeat, or if they suspect conditions such as metabolic disorders, diabetes, or liver disease. It may also be part of a broader evaluation for unexplained weight changes or hormonal imbalances.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the test if it’s part of a metabolic study. Avoid smoking and strenuous activity for a few hours beforehand. Bring any medications you’re currently taking.

During the Test

A healthcare professional will draw blood from a vein in your arm using a small needle. You may feel a brief pinch, but the procedure is quick and typically painless. You can usually resume normal activities immediately afterward.

What the Results Mean

Results help assess your energy metabolism and overall health. While specific ranges vary by lab, elevated levels may indicate conditions like diabetes, thyroid disorders, or starvation, while very low levels could suggest malnutrition or certain metabolic syndromes. Always discuss your results with your provider.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Free Fatty Acids (FFAs) - Serum/Plasma

Frequently asked questions

What causes free fatty acids to be tested?
Free fatty acids are tested primarily to evaluate metabolic health, diagnose conditions like diabetes, thyroid disorders, or fatty acid metabolism disorders, or assess responses to treatments (e.g., for weight management or hormonal imbalances). Your provider may also order it if you have symptoms like unexplained weight changes, fatigue, or irregular heart rhythms.
How do I prepare for this test?
No strict fasting is required unless specified by your provider, but avoid smoking and heavy meals for a few hours before the draw. If you’re on medications, check with your doctor to ensure they don’t affect results. Bring a list of medications and allergies to your appointment.
Can I take my usual medications before the test?
Yes, but always consult your healthcare provider first. Some medications (e.g., certain blood pressure or diabetes drugs) may influence FFA levels. Never skip doses without approval.
  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