eGFR (Cystatin C)
eGFR (cystatin C) estimates how well the kidneys filter the blood, using cystatin C, a protein made by all cells.
eGFR (cystatin C) estimates how well the kidneys filter the blood. It is based on cystatin C, a small protein made at a steady rate by all the body's cells and cleared by the kidneys. Because it depends less on muscle mass than creatinine, it suits people of very different builds. Retesting shows how it changes over time.
Cystatin C is less affected by muscle mass, diet and training than creatinine. It can still shift with age, smoking, a recent infection, thyroid hormone levels and some medicines, such as cortisone.
Foods that help
Water through the day, and plenty of vegetables, berries, leafy greens, olive oil and whole grains as part of a varied diet.
Foods to limit
Very salty and ultra-processed food, sugary drinks, and large amounts of red and processed meat.
Track it through the year
One value is a snapshot. Following it up shows whether what you changed is working.
Related markers
Educational information only — not a diagnosis. Every result is checked against safe limits, and anything critical is escalated for follow-up.
See all 84 markers →