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Interleukin-17 (IL-17) Serum Concentration

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

This test measures the amount of interleukin-17, a protein involved in the immune system that helps regulate inflammation. It may be checked if you have symptoms of autoimmune diseases or conditions linked to immune system overactivity.

Quick summary

["IL-17 helps your body fight infections but can also contribute to inflammation in certain diseases."]

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

Key facts at a glance

LOINC
99766-8
Short code
IL-17 CSF-mCnc
Synonyms
IL-17 CSF-mCnc
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may order this test to evaluate symptoms such as persistent skin rashes, joint pain, or unexplained inflammation. It could also be used to monitor conditions like psoriasis, rheumatoid arthritis, or other autoimmune disorders where IL-17 plays a role.

What to Expect Before the Test

No special preparation is typically needed. You may have a blood sample drawn from a vein in your arm. If you’re on blood-thinning medications, let your provider know before the test.

What the Results Mean

Results can vary depending on your health condition. Elevated levels may suggest an overactive immune response, while lower levels might indicate reduced immune activity. Your provider will discuss these results in the context of your overall health.

Common Conditions Monitored

IL-17 levels are often checked in people with autoimmune diseases like psoriasis, Crohn’s disease, or certain types of arthritis. It may also be useful in research or clinical trials studying immune-related disorders.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IL-17 Level

Frequently asked questions

What causes IL-17 levels to change?
IL-17 levels can be influenced by infections, autoimmune diseases, certain medications (like biologics), or genetic factors. Stress, diet, and overall health also play a role.
How often should I get this test?
Your provider will determine the frequency based on your condition and treatment plan. Some people may need it monthly, while others may only need it once.
Can diet or supplements affect IL-17 levels?
Dietary changes, such as reducing inflammatory foods (like processed sugars) or increasing omega-3s, may indirectly influence inflammation linked to IL-17. Always discuss supplements with your provider before use.
  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