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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 your body. It helps assess your kidney function.

Quick summary

["Cystatin C helps doctors check how well your kidneys are working."]

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

Key facts at a glance

LOINC
84917-4
Short code
Chr Y aneup Amn/CVS Ql FISH
Synonyms
Chr Y aneup Amn/CVS Ql FISH
Category
chemistry
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
fish
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your healthcare provider may order this test to monitor kidney health, especially if you have conditions like diabetes, high blood pressure, or a family history of kidney disease. It can also be used to track kidney function over time or before certain treatments that affect the kidneys.

How Is the Sample Collected?

A blood sample is taken from a vein, usually in your arm. You may feel a small pinch when the needle is inserted, but it usually goes away quickly. The sample is sent to a lab for testing.

What Do the Results Mean?

While specific reference ranges vary by lab, higher than expected levels of cystatin C may suggest kidney problems. Lower levels might indicate other conditions, but this test alone doesn’t diagnose anything. Your provider will interpret results in the context of your overall health.

What Are Common Causes of Abnormal Results?

Changes in cystatin C levels can occur with kidney disease, infections, dehydration, or certain medications. It can also rise slightly with age or during pregnancy.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Cystatin C

Frequently asked questions

Why might my cystatin C test be done regularly?
If you have a condition that affects your kidneys, like chronic kidney disease or diabetes, your doctor may check your cystatin C levels often to monitor how your kidneys are performing and adjust treatments as needed.
Can diet affect cystatin C levels?
Dietary changes alone won’t significantly affect cystatin C levels, but eating a balanced diet that supports kidney health (like reducing salt and protein if advised) can help manage overall kidney function.
What if my results are outside the normal range?
If your results are abnormal, your healthcare provider will discuss them with you and may recommend further tests or adjustments to your treatment plan. Never interpret results on your own—always talk to your doctor.
  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