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Chitinase-3-Like Protein (YKL-40) in Serum

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

This test measures the level of chitinase-3-like protein (YKL-40) in your blood, which may help assess inflammation or tissue damage.

Quick summary

["YKL-40 can provide insights into chronic inflammation and certain health conditions, though it’s not a standalone diagnostic tool."]

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

Key facts at a glance

LOINC
33111-6
Short code
GA from HC derived.Chitty 1997
Synonyms
GA from HC derived.Chitty 1997
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
us-estimated-from-hc-derived-chitty
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 Chitinase-3-Like Protein (YKL-40)?

Chitinase-3-like protein (YKL-40) is a protein produced by immune cells in response to inflammation or tissue injury. It’s not directly involved in digestion but is linked to conditions affecting the immune system, joints, or lungs.

Why Might You Need This Test?

Your healthcare provider may order this test to evaluate chronic inflammation, monitor conditions like rheumatoid arthritis, pulmonary fibrosis, or other inflammatory diseases, or assess response to treatment.

How Is the Test Performed?

A blood sample is drawn from a vein, typically in your arm. The sample is sent to a lab for analysis using a sensitive immunoassay method to measure YKL-40 levels.

What Do Results Mean?

Results may indicate elevated levels of YKL-40 if inflammation or tissue damage is present. However, interpretation depends on clinical context, including symptoms and other test results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

YKL-40 Serum Test

Frequently asked questions

What are the normal values for this test?
There are no universally standardized reference ranges for YKL-40 due to variability in conditions and testing methods. Your results will be compared to your specific clinical situation and other lab findings.
How often should I get this test?
Your healthcare provider will determine the frequency based on your medical needs, such as monitoring a chronic condition or evaluating symptoms of inflammation.
Can lifestyle changes affect YKL-40 levels?
While lifestyle factors like diet, exercise, and stress management may influence overall inflammation, their direct impact on YKL-40 levels isn’t well-defined. Discuss any concerns with your provider.
  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