Cystatin C Test
A small protein cleared by the kidneys. An alternative kidney-function marker, especially useful when muscle mass is unusual.
What is Cystatin C?
A small protein cleared by the kidneys. An alternative kidney-function marker, especially useful when muscle mass is unusual.
Cystatin C Reference Range
These are the typical adult reference ranges used by major US labs. Your report will include the specific range used by the lab that processed your sample.
| Population | Range |
|---|---|
| age 18–49 | 0.550 – 1.00 mg/L |
| age 50+ | 0.610 – 1.21 mg/L |
Reference ranges are educational. Always interpret your result with the specific range printed on your lab report and discuss anything outside the range with a clinician.
What your Cystatin C result may mean
Often reflects reduced kidney function. Less affected by diet and muscle mass than creatinine.
Educational only — not a diagnosis. Many factors can influence a single result. Discuss anything that concerns you with a healthcare provider.
Sources
Frequently asked
No. TestWell's licensed physician network reviews and approves your order — usually within minutes. You can place an order online without an in-person visit or a referral from your own doctor.
Ready to test your cystatin c?
Order in two minutes, get physician-approved, and visit a lab the same day. Starts at $36.99.