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Cystatin C, Serum Concentration (Quantitative)

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

This test measures the level of cystatin C, a protein produced by all cells in your body that helps regulate cell growth and division. It’s often used to assess kidney function.

Quick summary

["Cystatin C helps evaluate kidney health and may be used alongside other tests to check for kidney problems."]

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

Key facts at a glance

LOINC
34719-5
Short code
CMV DNA Amn Ql NAA+probe
Synonyms
CMV DNA Amn Ql NAA+probe
Category
chemistry
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
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 function, especially if you have a history of kidney disease, diabetes, high blood pressure, or other conditions that can affect kidneys. It can also be used to check kidney function before certain treatments or surgeries.

How Is the Sample Collected?

A small amount of blood is drawn from a vein, usually in your arm, by a healthcare professional. The blood sample is sent to a lab for testing.

What Should You Expect Before the Test?

No special preparation is usually needed for this test. However, if you’re taking certain medications or have specific health conditions, let your provider know before the test.

What Do the Results Mean?

Higher than expected levels of cystatin C may indicate kidney problems, while lower levels might suggest other health conditions. Your provider will interpret the results in the context of your overall health and medical history.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Cystatin C is a reliable marker for kidney function because it doesn’t depend on hydration status or muscle mass, unlike other kidney function tests like creatinine. It can help detect early kidney damage and monitor progression of kidney disease more accurately.

Short name

Cystatin C

Frequently asked questions

How often should I get this test if I have kidney issues?
Your provider will determine the frequency of testing based on your specific condition and how your kidneys are responding to treatment. Regular monitoring may be recommended if you have chronic kidney disease or other risk factors.
Does diet or hydration affect cystatin C levels?
Unlike some kidney function tests, cystatin C levels are less affected by hydration status or diet. However, certain medications or health conditions can influence results, so it’s best to follow your provider’s advice.
Can I still eat or drink normally before this test?
Yes, you can eat and drink as usual before this blood test. No special preparation is required unless your provider instructs otherwise.
  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