What do your Cystatin C levels mean?
The short answer
Nobody we follow has said what your Cystatin C should be. It comes up on the shows, but never with a number.
Your lab prints 0.6–1 mg/L. That range exists to catch disease, not to describe your best.
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?
Under 0.6 mg/L, your report marks it low. Between 0.6 and 1 it prints as normal. Over 1, your report marks it high. 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.