CST3 and acute kidney injury: Also, Ahlström et al. measured serum cystatin C daily starting from admission to the ICU in 202 patients.74 ARF (defined here as a threefold increase in baseline creatinine, or in case of chronic renal failure as an increase ≥0.5 to 4.0 mg/dL of creatinine, or diuresis ≤0.3 mL/kg/h for 24 h, or the need for RRT) occurred in 54 patients, and cystatin C was as useful as creatinine in detecting ARF.