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Serum Leucine Amino Acid Concentration (Mass Concentration)

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

This test measures the amount of the amino acid leucine in your blood serum. Leucine is one of the essential amino acids needed for muscle repair, protein synthesis, and overall metabolism.

Quick summary

["Leucine levels help assess protein metabolism and may be checked in conditions involving muscle breakdown or metabolic disorders."]

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

Key facts at a glance

LOINC
17074-6
Short code
Leucine Amn-aCnc
Synonyms
Leucine Amn-aCnc
Category
chemistry
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

Why Might This Test Be Ordered?

Your healthcare provider may order this test if you have symptoms or conditions linked to amino acid imbalances, such as muscle weakness, metabolic disorders, or certain genetic conditions. It may also be used to monitor treatment responses in patients with kidney disease or liver disorders.

What Does the Test Measure?

The test quantifies the mass concentration of leucine in your blood serum. Leucine is a branched-chain amino acid that plays a role in protein synthesis and energy production. Abnormal levels can indicate issues with metabolism or organ function.

Sample Collection and Preparation

A blood sample is drawn from a vein, usually in your arm. The blood is then processed to separate serum (the liquid part after clotting) for testing. This sample is sent to a lab where it is analyzed for leucine concentration using a specialized biochemical method.

What Are Common Causes of Abnormal Results?

Elevated leucine levels may be seen in conditions like uncontrolled diabetes, kidney disease, or certain metabolic disorders. Lower levels might be associated with severe malnutrition, liver disease, or specific genetic aminoacidopathies. Always discuss your results with your healthcare provider.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Leucine Level

Frequently asked questions

What Are My Next Steps If My Results Are Abnormal?
If your leucine levels are outside the expected range, your healthcare provider will review your medical history, symptoms, and other test results to determine the cause. They may recommend further testing, adjustments to your treatment plan, or referrals to specialists like a metabolic or nephrologist.
How Often Should I Have This Test?
The frequency of this test depends on your health condition and treatment plan. Your doctor will decide how often to repeat it based on your individual needs and responses to treatment.
Can I Take Anything Special Before This Test?
No special preparations are typically required for this test. However, avoid eating or drinking anything (except water) for at least 8 hours before your blood draw if instructed by your healthcare provider.
  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