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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 nucleated cells in your body. It helps assess kidney function.

Quick summary

["Cystatin C is a simple blood test to check how well your kidneys are working."]

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

Key facts at a glance

LOINC
72828-7
Short code
CT+NG DNA Pnl Spec
Synonyms
CT+NG DNA Pnl Spec
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 primarily used to evaluate kidney function, especially in people with diabetes or high blood pressure, where kidney damage may be more likely. It can also help monitor kidney health in patients on certain medications or those with chronic conditions that affect the kidneys.

How Is the Test Performed?

A small blood sample is drawn from a vein, usually in your arm. The sample is sent to a lab where it is analyzed to measure cystatin C levels. No special preparation is needed, but fasting is not required.

What Does a High or Low Level Mean?

Higher than expected levels may indicate kidney problems, while lower levels are less commonly associated with specific conditions but could suggest certain genetic factors or medications affecting protein production.

How Often Should This Test Be Done?

The frequency depends on your health status. Your healthcare provider will determine if and how often this test is needed based on your medical history, symptoms, and other tests.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Cystatin C is a useful marker for kidney function because it is produced continuously by all cells and does not depend on kidney filtration. It is often used alongside other tests, like creatinine, to get a more complete picture of kidney health, especially in people with conditions that may affect traditional kidney function tests.

Short name

Cystatin C

Frequently asked questions

Why might my doctor order a cystatin C test?
Your doctor may order this test to check for kidney disease, monitor kidney function in people with chronic health conditions, or evaluate kidney health in patients with certain genetic or metabolic disorders.
Is there any preparation needed before the test?
No special preparation is needed. You can eat and drink normally before the test, and you do not need to fast.
Can cystatin C levels change with diet or exercise?
Generally, diet and exercise do not significantly affect cystatin C levels, as it is produced by all cells in the body. However, certain medications or health conditions may influence the results, so it’s important to discuss any medications you’re taking with your healthcare 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