Isoleucine (Serum or Plasma Mass Concentration)
This test measures the amount of the amino acid isoleucine in your blood, either in serum or plasma. Amino acids are building blocks of proteins and play key roles in metabolism.
["Isoleucine levels help assess protein metabolism and may be checked in certain medical conditions."]
Key facts at a glance
- LOINC
- 47677-0
- Short code
- Isoleucine SFr Spec
- Synonyms
- Isoleucine SFr Spec
- 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 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 metabolic disorders, liver disease, or kidney problems. It may also be part of a broader evaluation for nutritional deficiencies or genetic conditions affecting protein metabolism.
What Does This Test Measure?
This test quantifies the concentration of isoleucine in your blood. Isoleucine is one of the essential amino acids your body needs to function properly, and abnormal levels can indicate underlying health issues.
Sample Collection and Preparation
Blood is drawn from a vein in your arm, and the sample is processed into either serum (after clotting) or plasma (after anticoagulant use). The test is typically performed on fresh or stored blood samples sent to a lab for analysis.
What Are Common Reasons for Monitoring?
Healthcare providers may monitor isoleucine levels in patients undergoing dialysis, those with inherited metabolic disorders (such as maple syrup urine disease), or individuals on certain diets or medications that affect amino acid metabolism.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Isoleucine Level
Frequently asked questions
Abnormally high or low levels of isoleucine can signal metabolic disorders, liver or kidney dysfunction, or other conditions affecting protein metabolism. Persistent imbalances may require medical intervention, such as dietary adjustments or specialized treatments.
An abnormal result may indicate an underlying metabolic issue, such as an inherited disorder or a condition affecting how your body processes amino acids. Your healthcare provider will discuss the results with you and may recommend further testing or adjustments to your treatment plan.
Results from this test are usually available within a few days to a week, depending on the lab’s processing time. Your healthcare provider will contact you to review the results and explain any findings.
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