Cystatin C

General Information:

In healthy people, blood concentrations of cystatin C remain relatively constant throughout life. If kidney function declines, the blood concentration rises.

Cystatin C is a small protein that is produced by all cells that contain a nucleus (i.e. the majority of cells in the body). In healthy people, it is produced and destroyed at a constant rate and is found in a variety of body fluids such as blood, spinal fluid, and breast milk.

Cystatin C may be used as an alternative to creatinine to look for and monitor kidney dysfunction in people with known or suspected kidney diseases. It is most useful in situations where creatinine measurement could be misleading: for instance in those who have liver cirrhosis, are very muscular, obese, malnourished or have a very small muscle mass (elderly, children or people with amputated limbs).

It can be useful in the early detection of chronic kidney disease (CKD), when other test results may still be normal and an affected person has few, if any, symptoms. There is some research suggesting that cystatin C returns to normal much more quickly than creatinine and could be used to assess kidney function in critically ill patients recovering in hospital.

Sample required:

Venous blood in morning in fasting

Key words:

Cystatin C, kidney, kidney disease