kidney · CysC
Cystatin C
A small protein filtered by the kidneys whose level barely depends on muscle mass, age, or diet — so it can give a cleaner kidney-function estimate than creatinine, especially at the borderline of reduced function.
This page is general wellness education, not medical advice. Your own lab’s reference range and your clinician’s interpretation always take precedence.
Typical reference range
| Group | General range |
|---|---|
| Adults | ~0.5–1.0 mg/L (assay-dependent) |
Units: mg/L. Ranges vary by lab and assay — read yours against the range printed on your own report.
What high Cystatin C can mean
- Reduced kidney function
- High-dose steroids
- Hyperthyroidism
What low Cystatin C can mean
- Generally not clinically concerning