Cystatin C with Glomerular Filtration Rate, Estimated (eGFR)

Catalog information reviewed: August 24, 2026 by the Sunridge Medical clinical team.

What this laboratory test evaluates

Cystatin C with Glomerular Filtration Rate, Estimated (eGFR)
This test measures the level of Cystatin C, a protein found in your body fluids, to assess kidney function. Unlike other markers, the level of Cystatin C's in the blood does not change due to infections, diet, or medication, making it a reliable indicator of how well your kidneys are filtering. The test also estimates your Glomerular Filtration Rate (eGFR), which indicates the rate at which your kidneys are filtering the blood. It's especially useful for people with unusual muscle mass or rapidly changing kidney function.

What patients is this test right for?This test is particularly beneficial for individuals with conditions that may affect muscle mass (like quadriplegics, the very elderly, or malnourished individuals) or those experiencing rapid changes in kidney function, such as hospitalized patients.

What type of sample is required for this test?1 mL serum.

Test ResourcesCurrently, no additional resources are provided.

Additional test information

Cystatin C with Glomerular Filtration Rate, Estimated (eGFR) – This test measures the level of Cystatin C, a protein found in your body fluids, to assess kidney function. Unlike other markers, the level of Cystatin C's in the blood does not change due to infections, diet, or medication, making it a reliable indicator of how well your kidneys are filtering. The test also estimates your Glomerular Filtration Rate (eGFR), which indicates the rate at which your kidneys are filtering the blood. It's especially useful for people with unusual muscle mass or rapidly changing kidney function.

Collection and processing

• Sample type: Serum
• Fasting: No
• Estimated laboratory processing: Results should be available in 2 – 5 business days after the sample is collected

How Sunridge uses laboratory information

Sunridge considers the medical question, symptoms, history, medications, prior results, and whether the finding could change care before recommending testing. A laboratory result is not interpreted in isolation and does not establish a diagnosis by itself.

Before requesting this test

Availability, collection requirements, eligibility, and processing estimates can change. Sunridge reviews each request and, when appropriate, creates the order through Fullscript. Follow the current instructions supplied with the approved order.