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Serum/plasma concentration of citrulline using immunoassay

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 and metabolic processes."]

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

Key facts at a glance

LOINC
73153-9
Short code
Sildenafil cit ind plt IgG SerPl Ql FC
Synonyms
Sildenafil cit ind plt IgG SerPl Ql FC
Category
hematology
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
flow-cytometry
CPT
82784
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 Is This Test Done?

Your healthcare provider may order this test if you have symptoms or conditions that could affect kidney function, such as dehydration, kidney disease, or metabolic disorders. It may also be part of broader evaluations for certain genetic or inherited metabolic conditions.

What Does the Result Mean?

Citrulline levels can vary based on health status, diet, and hydration. Abnormal results may signal underlying issues that need further investigation by your doctor.

What Preparations Are Needed?

No special preparation is typically required. You may be asked to fast for 8–12 hours before the test if instructed by your provider, but this is not always the case for citrulline.

How Is the Test Performed?

A blood sample is drawn from a vein, usually in your arm. The sample is sent to a lab where citrulline levels are measured using an immunoassay method.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Citrulline is a key intermediate in the urea cycle, which helps remove waste products from the blood. Low levels may indicate impaired kidney function, metabolic disorders, or certain genetic conditions. High levels could suggest overproduction or specific metabolic disturbances.

Short name

Citrulline Level

Frequently asked questions

What causes abnormal citrulline levels?
Abnormal levels may result from kidney disease, dehydration, certain medications, or metabolic disorders. Your doctor will consider your overall health and symptoms when interpreting results.
Is fasting required for this test?
Not always. Fasting may be recommended in some cases, but your provider will specify if needed. Always follow their instructions.
Can diet affect citrulline test results?
Yes, certain foods or supplements (like protein-rich diets) may influence amino acid levels. Avoiding high-protein meals for 24 hours before testing can help stabilize results.
  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