Cystatin C
Cystatin C is a small protein made by all the body’s cells and filtered out of the blood by the kidneys.
Cystatin C is a small protein made at a steady rate by all the body’s cells and filtered out of the blood by the kidneys. Unlike creatinine, it depends very little on muscle mass, so it adds context to kidney filtration when creatinine alone is hard to read. It is also used to calculate eGFR.
Some medicines, such as cortisone, and changes in thyroid hormone levels can affect cystatin C. Smoking and body weight may raise it slightly, and a recent infection can play a part.
Foods that help
Diet has little direct effect on cystatin C. Plenty of water, vegetables, berries, fatty fish and a balanced amount of salt, as part of a varied diet.
Foods to limit
A lot of salt and highly processed food, and large amounts of protein supplements.
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 →