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Serum Isoleucine Concentration (Mass Concentration)

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

This test measures the amount of the amino acid isoleucine in your serum. Amino acids are the building blocks of proteins and play key roles in metabolism.

Quick summary

["Isoleucine levels help assess protein metabolism and potential amino acid imbalances."]

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

Key facts at a glance

LOINC
47674-7
Short code
Isoleucine SFr Amn
Synonyms
Isoleucine SFr Amn
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 This Test Might Be Ordered

Your healthcare provider may order this test if you have symptoms like muscle weakness, fatigue, or unexplained weight changes that could suggest metabolic disorders. It may also be part of a broader evaluation for conditions affecting amino acid metabolism, such as certain genetic disorders or liver/kidney function issues.

What to Expect Before the Test

No special preparation is typically needed. You may fast for 8–12 hours before the test if instructed, but this is not always required. Bring any medications or supplements you’re taking to your appointment.

How the Test Is Performed

A blood sample is drawn from a vein in your arm by a healthcare professional. The blood is sent to a lab where it is analyzed for isoleucine levels using a specialized biochemical method.

What the Results Mean

Results are compared to standard reference ranges for healthy individuals. Abnormal levels may indicate metabolic disorders, liver disease, kidney problems, or other conditions affecting protein metabolism.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Isoleucine Level

Frequently asked questions

What causes abnormal isoleucine levels?
Abnormal levels can result from genetic metabolic disorders, liver or kidney disease, malnutrition, or certain medications that affect amino acid metabolism. Always discuss symptoms and test results with your healthcare provider.
How long does it take to get results?
Results are typically available within 1–3 business days, depending on lab processing times. Your provider will contact you once results are ready.
Can I eat or drink before this test?
Most tests do not require fasting, but follow any specific instructions your provider gives you. If fasting is required, avoid food and liquids (except water) for 8–12 hours before drawing blood.
  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