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Cerebrospinal Fluid (CSF) Ornithine Concentration

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

This test measures the level of ornithine, an amino acid found in your cerebrospinal fluid (the fluid surrounding the brain and spinal cord). It may be used to assess metabolic or neurological conditions.

Quick summary

["Ornithine levels in CSF can help diagnose or monitor certain metabolic disorders or neurological conditions."]

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

Key facts at a glance

LOINC
22647-2
Short code
Ornithine CSF-sCnc
Synonyms
Ornithine CSF-sCnc
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like confusion, seizures, or neurological issues that could be linked to metabolic disorders. It might also be part of a broader evaluation for conditions affecting the brain’s metabolism, such as urea cycle disorders or other inherited metabolic diseases.

What to Expect Before the Test

No special preparation is typically needed for this test. You may have a small amount of fluid (about 10–15 mL) drawn from your lumbar spine using a needle. The procedure is usually quick and painless, though you might feel a mild pinch or pressure. You’ll lie on your side with your knees bent, and the provider will insert the needle between your lower back bones.

What the Test Results Mean

Ornithine levels in CSF can vary widely depending on the underlying condition. Elevated levels might suggest certain metabolic disorders, while normal or low levels could help rule out specific diagnoses. Your results will be reviewed by a healthcare professional who can interpret them in the context of your overall health and symptoms.

Common Conditions Monitored

This test is often used to investigate conditions like urea cycle disorders (e.g., argininosuccinic aciduria), organic acidemias, or other inherited metabolic diseases that affect amino acid metabolism in the brain. It may also be part of a diagnostic workup for unexplained neurological symptoms or seizures.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CSF Ornithine

Frequently asked questions

How does ornithine in CSF relate to my health?
Ornithine is an intermediate in the urea cycle, a process that helps remove waste products from your blood. Abnormal levels in CSF can indicate metabolic imbalances that may affect brain function. If your levels are elevated, it may point to a genetic or metabolic disorder that requires further testing or treatment.
What if my test results are abnormal?
If your results show abnormal ornithine levels in CSF, your doctor may recommend additional tests, such as genetic testing or further metabolic studies, to identify the cause. Treatment might include dietary changes, medications, or other interventions depending on the diagnosis.
Is this test painful?
The procedure for drawing CSF is generally quick and well-tolerated. Most people experience only mild discomfort or pressure during the needle insertion. If you have concerns, discuss them with your healthcare provider before the test.
  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