Serum/plasma citrulline concentration
This test measures the amount of citrulline, an amino acid involved in the urea cycle, which helps remove waste products from your blood. It may be used to assess liver function or metabolic health.
["Citrulline levels can help diagnose or monitor conditions affecting liver function or urea cycle disorders."]
Key facts at a glance
- LOINC
- 53506-2
- Short code
- Citrulline SFr Plas
- Synonyms
- Citrulline SFr Plas
- Category
- chemistry
- Sample
- plasma
- Container
- Lavender-top (EDTA) or Green-top (Heparin)
- 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 This Test Might Be Ordered
Your healthcare provider may recommend this test if you have symptoms or conditions linked to liver issues, such as liver disease, metabolic disorders, or urea cycle defects. It could also be part of routine monitoring for patients with known kidney or liver problems.
What to Expect Before the Test
No special preparation is typically needed, but you may be asked to fast for a few hours before the blood draw if your test includes fasting components. Bring any medications or supplements you’re currently taking to your appointment.
How the Test Works
A small sample of your blood (either serum or plasma) is collected and sent to a lab. The lab measures the concentration of citrulline using a specialized analytical method, often an immunoassay or enzymatic technique, to detect and quantify the amino acid.
What the Results Mean
Results are usually reported as a concentration value (e.g., micromoles per liter). While reference ranges vary by lab, abnormal levels may signal underlying metabolic or liver conditions that need further evaluation.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated citrulline levels may indicate impaired liver function, urea cycle disorders, or conditions affecting ammonia metabolism. Low levels could suggest deficiencies in enzymes involved in the urea cycle or other metabolic disturbances. Always discuss results with your healthcare provider for personalized interpretation.
Short name
Citrulline Level
Frequently asked questions
What causes abnormal citrulline levels?
How often should I get this test?
Can diet affect citrulline levels?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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