Cystatin C Test Levels, Normal Range + How to Lower it

Cystatin C is important for monitoring kidney function, but is there more to this marker? Read on to uncover how cystatin C can impact your health.

What is Cystatin C?

Cystatin C is a protein that inhibits the breakdown of other proteins. It is produced by most cells in the body and can be found in all bodily fluids [1, 2, 3].

This protein plays a variety of roles: it’s involved in growth, bone metabolism, and studies suggest it protects the brain against injury and some neurodegenerative diseases [4, 5].

Cystatin C is almost completely broken down in the kidneys (>99%). In healthy people, both the production and the breakdown of this protein happen at a relatively constant rate. But if your kidneys are not working properly, cystatin C builds up in the blood [6, 7, 8]. That is why this molecule can tell us how well our kidneys are working.