Cystatin C Unit Converter

Cystatin C is a small protein (13 kDa) produced at a constant rate by all nucleated cells in the body. It functions as a cysteine protease inhibitor and is found in blood and other body fluids.

The kidneys filter cystatin C from the blood, then reabsorb and break it down in the tubules. Because of this, cystatin C levels in blood reflect how well the kidneys are filtering. Higher levels suggest reduced kidney function, while lower levels indicate better filtration.

Unlike creatinine, cystatin C is less affected by muscle mass, age, sex, or race. This makes it particularly useful for estimating kidney function in people where creatinine may be unreliable, such as the elderly, bodybuilders, or those with abnormal muscle mass.

Cystatin C is produced at a constant rate by all nucleated cells throughout the body. Unlike creatinine, which comes primarily from muscle metabolism, cystatin C production is not significantly influenced by muscle mass or diet.