What is Cystatin C, and why is it useful?
Cystatin C is a low-molecular-weight protein produced at a relatively constant rate by all nucleated cells. It is freely filtered by the glomeruli and then metabolised in the proximal tubules. Unlike creatinine, it is much less dependent on muscle mass or dietary meat intake. Combining both markers partly offsets their separate non-GFR determinants and generally provides a more accurate eGFR. However, inflammation, adiposity, smoking, thyroid dysfunction and glucocorticoids may influence Cystatin C.
CKD Assessment Beyond Creatinine