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Very Long Chain Fatty Acids Profile (Serum/Plasma)

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

This test measures levels of very long-chain fatty acids in your blood, which can help assess metabolic function and identify conditions like peroxisomal disorders.

Quick summary

["VLCFA levels may indicate genetic or metabolic issues affecting fat breakdown."]

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

Key facts at a glance

LOINC
34169-3
Short code
VLCFA SerPl-mCnc
Synonyms
VLCFA SerPl-mCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Is Done

Your healthcare provider may order this test if you have symptoms like developmental delays, neurological problems, or signs of metabolic disorders. It’s also used in genetic testing for inherited conditions affecting fat metabolism.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before drawing blood. Bring any medications or supplements you’re taking to your appointment.

What the Test Measures

The test detects specific fatty acids (e.g., C24:0, C26:0) using high-performance liquid chromatography (HPLC), which helps identify abnormal fat breakdown patterns.

Possible Conditions Linked to Abnormal Results

High or low levels of VLCFAs may signal peroxisomal disorders (e.g., Zellweger syndrome), Refsum disease, or other rare metabolic conditions requiring specialized care.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

VLCFA Profile

Frequently asked questions

What does a ‘normal’ result mean for me?
A ‘normal’ result means your fatty acid levels fall within expected ranges for your age and health status, but follow-up may still be needed if you have symptoms or a family history of metabolic disorders.
Can diet or supplements affect this test?
Avoid high-fat foods or supplements (e.g., omega-3s) for 24 hours before testing to ensure accurate results. Your provider will guide you on fasting rules.
Will I need follow-up tests if my results are abnormal?
Yes, abnormal results may prompt additional testing (e.g., genetic analysis, enzyme activity checks) to confirm a diagnosis and guide treatment, such as dietary modifications or enzyme replacement therapy.
  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