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Soluble Interleukin-2 Receptor, Serum/Plasma — Concentration

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

Measures soluble interleukin-2 receptor in blood, a marker of immune-cell activation that can be elevated with immune, inflammatory, or lymphoproliferative conditions.

Quick summary

["An elevated soluble IL-2 receptor level can signal increased immune-system activation, but it must be interpreted alongside other findings."]

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

Key facts at a glance

LOINC
44422-4
Short code
Sol IL2RA SerPl-aCnc
Synonyms
Sol IL2RA SerPl-aCnc
Category
liver
Sample
serum
Container
Red-top tube (SST)
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

What is this test?

This blood test measures the concentration of soluble interleukin-2 receptor, also called soluble IL-2 receptor or sIL-2R. The receptor is released by activated immune cells and can be detected in serum or plasma.

Why might I need this test?

It may be used to help evaluate immune-system activity, particularly in people with suspected lymphoproliferative disorders, autoimmune conditions, or certain inflammatory diseases. It may also be used in follow-up or research-related clinical assessments.

How is the test performed?

A blood sample is collected, and the soluble IL-2 receptor concentration is measured using a laboratory assay, commonly an immunoassay. No special equipment is needed at home, and results are usually available after the sample is processed.

How do I prepare for the test?

Fasting is generally not required for this test, although the laboratory may have specific instructions. Tell your clinician about immune-modifying medicines, recent infections, vaccinations, and any history of immune or lymphoproliferative conditions because these can affect interpretation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Soluble IL-2 receptor

Frequently asked questions

Does a high soluble IL-2 receptor level mean I have cancer?
No. Elevated levels can occur with several immune and inflammatory conditions as well as some blood cancers, so this result cannot diagnose cancer by itself.
What is the difference between soluble IL-2 receptor and IL-2?
IL-2 is a signaling protein involved in immune-cell activity, while soluble IL-2 receptor is a released form of the receptor that can be measured in blood. Each reflects a different part of the immune response.
Is fasting required before this blood test?
Fasting is usually unnecessary. Follow the testing laboratory's instructions and discuss any medicines or recent infections with your clinician.
  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