Serum/plasma concentration of a specific protein marker for renal function (e.g., cystatin C)

Why Is This Test Done?

Your doctor may order this test to check for kidney problems, monitor kidney disease progression, or evaluate kidney function in people with other health conditions, such as diabetes or high blood pressure. It can also help determine if you need dialysis or other kidney treatments.

How Is the Test Performed?

A small blood sample is taken from a vein, usually in your arm. The blood is sent to a lab where it is analyzed to measure cystatin C levels using a sensitive immunoassay or nephelometry method.

What Do Results Mean?

Higher than expected levels of cystatin C may suggest kidney damage or disease, while lower levels might indicate conditions that affect protein production or kidney function differently. Results are compared to a general reference range for your age and health status.

Common Conditions Monitored

This test is often used alongside creatinine tests to better assess kidney function, especially in people with chronic kidney disease, those on dialysis, or those with conditions like lupus, diabetes, or certain medications that can affect kidney health.