Cystatin C as a marker of GFR--history, indications, and future research.

Objective: To summarize recent knowledge on the small molecular weight protein cystatin C (cys-C) and its use as a marker of the glomerular filtration rate (GFR).

Methods: A multinational expert meeting was held in April 2002 in Marburg, Germany. Contributors summarized their main findings.

Conclusions: Cys-C is at least equal if not superior to serum creatinine as a marker of GFR. The independence from height, gender, age, and muscle mass is advantageous. Select patient groups such as children, the elderly, and patients with reduced muscle mass benefit in particular.