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Soluble Interleukin-1 Receptor Antagonist, Serum/Plasma — Mass Concentration

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

Measures soluble IL-1 receptor antagonist in blood, a marker associated with the body's inflammatory response.

Quick summary

["This blood test can help assess inflammatory immune activity, but results must be interpreted with your symptoms and other findings."]

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

Key facts at a glance

LOINC
55927-8
Short code
Sol IL1RA SerPl-mCnc
Synonyms
Sol IL1RA SerPl-mCnc
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 test measures soluble interleukin-1 receptor antagonist, also called sIL-1Ra, in serum or plasma. This protein is released by the immune system and helps regulate inflammation.

Why might I need this test?

This test may be used in selected situations to evaluate inflammatory activity, particularly in research or specialized clinical settings. It is generally interpreted alongside symptoms, medical history, and other laboratory tests.

How is the test performed?

A blood sample is collected and separated into serum or plasma. The laboratory then measures the amount of sIL-1Ra using a validated laboratory assay.

How do I prepare for the test?

Fasting is usually not required, but follow any instructions provided by the ordering clinician or laboratory. Tell the healthcare team about medicines or supplements that may affect inflammation or test results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Higher sIL-1Ra levels may occur when the inflammatory immune system is active, including with infection, autoimmune disease, tissue injury, or other inflammatory conditions. Lower levels and their clinical meaning are less clearly established, so an abnormal result does not identify a specific disease by itself.

Short name

Soluble IL-1 Receptor Antagonist

Frequently asked questions

Does a high result mean I have an autoimmune disease?
No. An elevated level is nonspecific and may occur with many inflammatory conditions. A clinician must interpret it with your symptoms, examination, and other tests.
Is this test the same as an IL-1 receptor antibody test?
No. This test measures a naturally occurring regulatory protein called soluble IL-1 receptor antagonist, not antibodies against the receptor.
Is this a routine blood test?
It is not routinely performed for most patients and is more often used in selected clinical evaluations or research. Your healthcare professional can explain why it was ordered.
  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