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Cystatin C (Serum) Concentration

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

This test measures the level of cystatin C, a protein produced by all cells in the body that helps assess kidney function.

Quick summary

["Cystatin C helps monitor kidney health and may be used alongside other tests to check for kidney damage or disease."]

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

Key facts at a glance

LOINC
37210-2
Short code
CT Guided Abd Cyst asp
Synonyms
CT Guided Abd Cyst asp
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ct
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 Cystatin C Used For?

Cystatin C is often used to evaluate kidney function, especially in people with diabetes, high blood pressure, or a family history of kidney problems. It can also help determine how well your kidneys are filtering waste products from your blood, which is important for preventing long-term damage.

How Is the Test Performed?

A small blood sample is drawn from a vein, usually in your arm. The blood is sent to a lab where it is analyzed to measure cystatin C levels using a specialized immunoassay method.

Why Might You Need This Test?

Your healthcare provider may order this test if you have symptoms like fatigue, swelling, frequent urination, or if you have a condition that puts you at higher risk for kidney issues, such as chronic kidney disease or certain medications that affect kidney function.

What Do Results Mean?

Higher than expected cystatin C levels may indicate reduced kidney function, while lower levels might suggest overproduction of the protein or other conditions. Results are interpreted by your doctor in the context of your overall health and other tests.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Cystatin C

Frequently asked questions

How often will I need this test?
The frequency depends on your health status. If you have kidney disease, your doctor may recommend regular monitoring to track changes in your cystatin C levels and kidney function over time.
Can I eat or drink anything before the test?
No special preparation is needed for this test. However, always follow your healthcare provider’s instructions, as some tests may require fasting or avoiding certain foods/drinks.
What are the possible side effects of the blood draw?
The most common side effect is mild bruising, redness, or soreness at the needle site. Rarely, you might feel lightheaded or experience a small amount of bleeding. Most side effects are minor and resolve quickly.
  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