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Postprandial Fasting Serum Fatty Acid Profile (Long-chain and Medium-chain Fatty Acids)

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

This test measures the levels of certain fatty acids in your blood after eating, helping assess how your body processes fats. It may be used to evaluate metabolic health or dietary absorption.

Quick summary

["Understanding how your body handles fats after eating can help identify potential digestive or metabolic issues."]

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

Key facts at a glance

LOINC
36056-0
Short code
MR Post fossa
Synonyms
MR Post fossa
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
mr
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 unexplained weight changes, digestive issues, or signs of metabolic disorders. It could also be part of a broader evaluation for conditions like fatty acid metabolism disorders or gastrointestinal problems.

What to Expect Before the Test

You’ll need to fast for 12 hours before the test, then eat a standard meal within a specific timeframe afterward. Blood will be drawn from a vein in your arm. Avoid alcohol and certain medications for a few days before testing.

What the Results Mean

Results show the concentration of different fatty acids in your blood post-meal. Abnormal levels may indicate problems with fat digestion, absorption, or metabolism, but your provider will interpret these with clinical context.

Common Conditions Monitored

This test helps monitor conditions like medium-chain triglyceride disorders, cystic fibrosis, or other metabolic or digestive disorders that affect fat metabolism.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Post-meal Fat Analysis

Frequently asked questions

What does a postprandial fatty acid test involve?
It involves fasting before eating, then eating a meal and having blood drawn at a set time afterward to measure fatty acid levels.
How long should I fast before this test?
You should fast for at least 12 hours before the test, typically overnight.
Can I take my usual medications before this test?
Some medications may affect results, so check with your healthcare provider to see if you should adjust your routine before testing.
  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