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Citrulline in Serum or Plasma (Mass Concentration)

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

This test measures the amount of citrulline, an amino acid, in your blood. It may be used to assess kidney function or metabolic health.

Quick summary

["Citrulline helps evaluate kidney function and certain metabolic processes."]

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

Key facts at a glance

LOINC
9511-7
Short code
Citrulline CSF-mCnc
Synonyms
Citrulline CSF-mCnc
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 or conditions that could affect how your body processes amino acids, such as kidney disease, liver disease, or metabolic disorders. It might also be part of monitoring for urea cycle disorders or evaluating nutritional status.

What to Expect Before the Test

No special preparation is typically needed. You may be asked to fast for a few hours before the blood draw, but always follow your provider’s instructions. Avoid strenuous activity the day of the test.

How the Test Is Performed

A healthcare professional will draw blood from a vein, usually in your arm. The blood sample will be sent to a lab for analysis using a high-performance liquid chromatography (HPLC) method to measure citrulline levels.

What the Results Mean

Results are compared to a reference range specific to your lab. Abnormal levels may suggest underlying health issues, but interpretation depends on clinical context, including your symptoms and other test results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Elevated or Low Citrulline Levels

Short name

Citrulline Level

Frequently asked questions

What might cause elevated citrulline?
Elevated citrulline can occur in kidney disease, liver dysfunction, or certain metabolic disorders. It may also be influenced by medications or dietary factors. Your provider will consider these factors when evaluating your results.
What might cause low citrulline?
Low citrulline levels may indicate issues with amino acid metabolism, such as urea cycle disorders, or could be due to malnutrition or certain medications. Always discuss results with your healthcare provider.
How often should this test be repeated?
The frequency depends on your diagnosis and treatment plan. If this test is part of ongoing monitoring, your provider will determine how often to repeat it based on your health status and responses to treatment.
  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