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Isoleucine concentration in hair

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

This test measures the amount of the amino acid isoleucine found in a hair sample, often used to assess long-term protein metabolism or nutritional status over time.

Quick summary

["Hair isoleucine testing may help evaluate overall protein intake or metabolic health."]

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

Key facts at a glance

LOINC
47672-1
Short code
Isoleucine SFr Hair
Synonyms
Isoleucine SFr Hair
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 Is This Test Done?

Hair isoleucine testing may be ordered if you have concerns about long-term protein metabolism, nutritional deficiencies, or conditions affecting amino acid balance. It can provide insights into dietary habits or metabolic processes that may not be detectable through blood tests alone.

What Does the Result Mean?

Results are typically reported as a concentration of isoleucine in the hair sample. While reference ranges can vary by lab, higher levels may suggest adequate protein intake, while lower levels could indicate potential deficiencies or metabolic issues.

How Is the Test Performed?

A small sample of hair is collected, usually from the scalp or other areas. The hair is then processed in a laboratory to measure the concentration of isoleucine. This test does not require fasting and is generally a non-invasive procedure.

What Are Possible Results?

Results may show elevated, normal, or reduced levels of isoleucine in the hair sample. Interpretation depends on clinical context, such as your overall health, diet, or symptoms you may be experiencing.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Hair Isoleucine Level

Frequently asked questions

What might cause abnormal results?
Hair isoleucine levels can be influenced by dietary protein intake, metabolic disorders, or certain genetic conditions. Abnormal results may prompt further evaluation, including blood tests or dietary counseling, to identify underlying causes.
How long does it take to get results?
Results are typically available within 1 to 2 weeks after the sample is processed, depending on lab turnaround times.
Is this test covered by insurance?
Coverage depends on your insurance plan and the clinical indication for the test. Always check with your healthcare provider or insurance company before proceeding.
  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