Cystatin C, Serum Concentration (Quantitative)

Why Is This Test Done?

Your healthcare provider may order this test if you have symptoms of kidney problems, such as fatigue, swelling, or frequent urination. It’s also used to monitor kidney function in people with diabetes, high blood pressure, or other conditions that can affect the kidneys over time. Sometimes, it’s used alongside other tests to better evaluate kidney function, especially in cases where traditional kidney function tests (like creatinine) might not be reliable.

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. The result is typically available within a few days.

What Do the Results Mean?

Higher than expected cystatin C levels may indicate kidney problems, including reduced kidney function. Lower levels might suggest other health conditions or medications that affect protein production. Your healthcare provider will interpret the results in the context of your overall health and other tests.

Common Causes of Abnormal Results

Elevated cystatin C levels can be caused by kidney disease, infections, muscle disorders, or certain medications. Lower levels may be linked to conditions that reduce protein production or certain genetic factors. Always discuss any changes in your results with your doctor.