Serum Leucine Amino Acid Concentration (Mass Concentration)
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 and protein synthesis.
["Leucine helps your body build muscle and maintain protein levels; abnormal results may signal metabolic or muscle-related conditions."]
Key facts at a glance
- LOINC
- 13403-1
- Short code
- Leucine Amn-mCnc
- Synonyms
- Leucine Amn-mCnc
- 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
What Does This Test Measure?
Leucine is a branched-chain amino acid (BCAA) that plays a key role in muscle metabolism and protein production. Your body uses it to repair tissues, produce energy, and support overall protein function. This test helps assess whether your leucine levels are within normal ranges for your health status.
Why Might You Need This Test?
Doctors may order this test if you have symptoms like muscle weakness, unexplained fatigue, or conditions affecting metabolism (e.g., liver disease, kidney issues, or certain genetic disorders). It can also be part of monitoring for muscle wasting or nutritional deficiencies.
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 blood draw if your doctor specifies. Wear loose clothing and fasten your shirt for easy access. Bring any medications or supplements you take daily to discuss with your provider.
What Happens 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 it’s usually over quickly. The blood sample is then sent to a lab for analysis of leucine concentration.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated leucine levels may indicate conditions like liver disease, kidney problems, or certain metabolic disorders. Low levels could suggest muscle breakdown, malnutrition, or disorders affecting amino acid metabolism. Your doctor will interpret results in the context of your symptoms and overall health.
Short name
Leucine Level
Frequently asked questions
How long does it take to get results?
What does a normal range mean for me?
Can lifestyle changes affect leucine levels?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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