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Serum or plasma concentration of free fatty acids (medium-chain and long-chain)

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

This test measures the levels of free fatty acids in your blood, which are important energy sources for your body. They help regulate metabolism and energy balance.

Quick summary

["Free fatty acids play a key role in energy production and metabolic health."]

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

Key facts at a glance

LOINC
33113-2
Short code
GA from HC.Jeantyy82
Synonyms
GA from HC.Jeantyy82
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
us-estimated-from-hc-jeanty
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 of metabolic disorders, such as unexplained weight changes, fatigue, or signs of high or low energy metabolism. It could also be part of a broader evaluation for conditions like diabetes, thyroid disorders, or liver disease.

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 involves a blood draw. Avoid strenuous exercise or consuming certain medications that could affect results.

How the Test Works

A small sample of your blood (serum or plasma) is collected and analyzed to measure free fatty acid levels. The test may use methods like enzymatic or chemiluminescent immunoassay to detect these compounds.

What the Results Mean

Results help assess energy metabolism, detect abnormalities in fat breakdown, and identify potential metabolic or endocrine disorders. Elevated levels may suggest conditions like diabetes or hyperthyroidism, while low levels could indicate malnutrition or thyroid issues.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Free Fatty Acids in Health and Disease

Short name

Free Fatty Acids (FFA) Profile

Frequently asked questions

What could cause abnormal results in this test?
Abnormal results may be linked to metabolic disorders, such as uncontrolled diabetes, thyroid dysfunction, or conditions affecting fat metabolism. Other factors like fasting, medications, or recent illness could also influence results.
How often should I get this test?
Your doctor will determine the frequency based on your health needs, symptoms, or ongoing conditions. Routine screening isn’t typically recommended unless you have specific risk factors or symptoms.
Can lifestyle changes affect this test?
Yes, diet, exercise, and certain medications can impact free fatty acid levels. If you’re making changes, discuss them with your provider to ensure accurate results.
  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