Cystatin C

The Cystatin C test is a laboratory blood test designed to evaluate kidney function, particularly the glomerular filtration rate (GFR), which indicates how efficiently the kidneys filter blood. Cystatin C is a protein constantly produced by all cells in the body and is removed from the blood by the kidneys. Since its concentration is less dependent on age, gender, or muscle mass than creatinine, this marker is considered a more sensitive indicator of early changes in kidney function.

Elevated levels of Cystatin C in the blood may indicate reduced kidney filtration function, even when other indicators are still within normal limits. The test helps to detect kidney function disorders early and assess their condition more accurately.

Who is this test for?

The test is recommended for individuals who want to:

• assess kidney filtration function and its changes;
• detect potential kidney function disorders early;
• refine the glomerular filtration rate (GFR), especially when creatinine indicators may be less accurate;
• monitor kidney function in chronic diseases (e.g., diabetes or hypertension);
• evaluate kidney condition before prescribing certain medications or treatments.

The test can be performed both preventively and to more accurately evaluate potential kidney function disorders.

When is it recommended to perform?

The test is especially useful if:

• there is an increased risk of kidney diseases (e.g., with diabetes or high blood pressure);
• creatinine test results are questionable or borderline;
• more precise evaluation of kidney function is needed in children, older adults, or individuals with low/high muscle mass;
• potential signs of kidney function disorder are observed (e.g., swelling, fatigue, changes in urination);
• an already diagnosed kidney disease or its progression is being monitored.

What will you learn from the test?

After performing the Cystatin C test, the patient will receive information about:

• the concentration of Cystatin C in the blood;
• assessment of kidney filtration function (GFR);
• early changes in kidney function;
• whether the kidneys effectively remove substances from the body;
• whether additional tests or a doctor's consultation may be needed.

This test provides important information about kidney function, allows early detection of function disorders, helps to assess the body's condition more accurately, and aids in making appropriate further diagnostic or treatment decisions.