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Serum Isoleucine Concentration

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

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

Quick summary

["Isoleucine levels help assess protein metabolism and potential metabolic disorders."]

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

Key facts at a glance

LOINC
26730-2
Short code
Isoleucine Amn-sCnc
Synonyms
Isoleucine Amn-sCnc
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 recommend this test if you have symptoms like muscle weakness, fatigue, or unexplained weight changes. It could also be part of a broader evaluation for conditions affecting amino acid metabolism, such as inherited disorders or kidney function issues.

What to Expect Before the Test

No special preparation is typically needed. You may be asked to fast for 8–12 hours before the test if it’s part of a metabolic study, but this isn’t always required. Bring any medications you’re taking to your appointment.

During the Test Process

A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch or discomfort, but it usually lasts only a few seconds. The blood sample will be sent to a lab for analysis.

What the Results Mean

Results are usually reported as a concentration in milligrams per deciliter (mg/dL). While reference ranges vary by lab, abnormal levels may signal metabolic imbalances, kidney problems, or certain genetic conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Isoleucine Level

Frequently asked questions

What causes isoleucine levels to be checked?
Isoleucine testing is often part of a metabolic workup if you have symptoms like unexplained fatigue, muscle weakness, or signs of amino acid disorders. It may also be used to monitor conditions like kidney disease or certain inherited metabolic syndromes.
How long does it take to get results?
Results are typically available within 1–3 business days, depending on your lab and testing volume. Your provider will contact you once they’re ready.
Can I eat or drink before this test?
Most of the time, no fasting is required, but confirm with your provider if this test is part of a metabolic study. If fasting is needed, follow their instructions carefully to avoid misleading results.
  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