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Serum or plasma ornithine concentration

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

This test measures the amount of ornithine, an amino acid involved in the body’s urea cycle, which helps remove waste products from metabolism.

Quick summary

["Ornithine levels may be checked to assess liver function or metabolic health."]

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

Key facts at a glance

LOINC
27219-5
Short code
Ornithine Amn-sCnc
Synonyms
Ornithine 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 Is This Test Done?

Your healthcare provider may order this test if you have symptoms of liver disease, such as fatigue, jaundice (yellowing of skin/eyes), or confusion. It can also be part of evaluating conditions like urea cycle disorders or metabolic imbalances.

What Does It Measure?

Ornithine is a key intermediate in the urea cycle, where ammonia—a toxic byproduct of protein metabolism—is converted into urea for excretion. Abnormal levels may indicate dysfunction in this cycle.

Sample Collection and Preparation

Blood is drawn from a vein, usually in your arm. The sample is processed into serum or plasma for testing. This test is typically done on fresh or stored samples, depending on the lab’s protocol.

Possible Causes of Abnormal Results

Low ornithine levels may suggest liver disease, urea cycle enzyme deficiencies, or certain genetic disorders. High levels could indicate overproduction of ammonia or rare metabolic conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Ornithine Level

Frequently asked questions

Could I get false results from diet or medications?
Dietary protein intake may influence ornithine levels, so fasting may be recommended. Certain medications (e.g., some antibiotics or diuretics) could also affect results, so discuss your full medication list with your provider.
What if my results are outside the normal range?
Your provider will review your results alongside other tests and your medical history to determine if further evaluation (like additional bloodwork or genetic testing) is needed.
How often should I get this test?
Frequency depends on your health condition. If you have a chronic liver or metabolic disorder, your provider may schedule follow-up tests as needed to monitor changes in your condition.
  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