What is a normal cystatin C level?
The short answer
A typical US lab prints a normal cystatin C range of 0.6–1 mg/L. That range exists to catch disease, not to describe your best.
Nobody we follow has said what your Cystatin C should be. It comes up on the shows, but never with a number.
What Cystatin C measures
A protein your kidneys filter out. Muscle mass does not move it, which is where it differs from creatinine.
It gives a clearer read on kidney filtration in people with a lot of muscle, and in people who are frail.
Common questions
What is a normal Cystatin C level?
Most US labs print 0.6–1 mg/L. Your report grades you against that range. It exists to catch disease, not to describe your best.
What does your Cystatin C number mean?
On a typical lab range, under 0.6 mg/L is low, 0.6 to 1 is normal and over 1 is high. Your own report prints its range next to your number, and that is the one your lab uses. Nobody we follow has drawn a line inside that range.
What does the Cystatin C test measure?
A protein your kidneys filter out. Muscle mass does not move it, which is where it differs from creatinine. It gives a clearer read on kidney filtration in people with a lot of muscle, and in people who are frail.
Why is there no target here?
Because nobody we follow has named a number for Cystatin C. If that changes, it will be here.