Cystatin C is a protein made by all cells and filtered by the kidneys. Unlike creatinine, it is not affected by muscle mass.
- Normal range (adults)
- 0.6–1 mg/L
- Sample
- Blood
- Fasting
- Not usually needed
- Also called
- Cystatin-C, CysC, Serum Cystatin C
Cystatin C normal range
| Group | mg/LSame unit in all countries |
|---|---|
| Adults | 0.6–1 |
Ranges vary slightly between laboratories. The range printed on your own report is the one to go by.
Why is the Cystatin C test done?
It is used to confirm kidney function when creatinine may be misleading, for example in elderly, very muscular or very thin people.
What does a high Cystatin C level mean?
A high cystatin C indicates reduced kidney filtering.
Common causes
- Chronic kidney disease
- Thyroid disorders
- High-dose steroids
Diet and lifestyle tips
- Same as for reduced kidney function: control blood sugar and pressure, limit salt, avoid painkillers
When should you see a doctor?
Discuss a raised cystatin C with your doctor alongside your eGFR.
Last updated
This page is for general education and is not a diagnosis. Normal ranges differ between laboratories, so always compare your result with the reference range printed on your own report, and discuss abnormal results with your doctor.