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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 levels can help evaluate kidney function and certain metabolic processes."]

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

Key facts at a glance

LOINC
34266-7
Short code
Citrate Ur-sCnc
Synonyms
Citrate Ur-sCnc
Category
chemistry
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
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 may also be part of a broader evaluation for urea cycle disorders or to monitor treatment for conditions like hyperammonemia.

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. Avoid excessive protein intake on the day of testing. If you’re on medications, let your provider know beforehand.

During the Test Process

A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch, but it usually doesn’t cause discomfort. The blood sample will be sent to a lab for analysis.

What the Results Mean

Results are compared to a reference range for your age, sex, and health status. Abnormally high or low levels may signal underlying health concerns that need further investigation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated citrulline levels may indicate impaired kidney function, liver disease, or urea cycle enzyme deficiencies. Low levels could suggest metabolic disorders or conditions affecting amino acid metabolism. Always discuss results with your healthcare provider for personalized interpretation.

Short name

Serum/Citruline

Frequently asked questions

What causes abnormal citrulline levels?
Abnormal results may be linked to kidney problems, liver disease, or metabolic disorders like urea cycle defects. Other factors, such as certain medications or fasting, can also influence levels.
How long will it take to get my results?
Results are typically available within 1–3 business days, depending on your lab’s processing time. Your provider will contact you once they are ready for review.
Can I eat or drink anything before this test?
Avoid excessive protein intake on the day of testing, but you can usually have clear liquids unless instructed otherwise. Follow your provider’s specific guidelines for fasting if required.
  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