ST AIA-PACK Cystatin C

Human Cystatin C is a basic protein with low molecular mass (13 kDa) in the cystatin superfamily. Cystatin C is produced at a constant rate in all nucleated cells. The function of Cystatin C seems to be to protect connective cell or tissue from destruction by intracellular enzymes. The gene is of the house-keeping type, which is compatible with a stable production rate of Cystatin C by most cell types, even under inflammatory conditions. Cystatin C is not an acute phase reactant. Due to its small size, it is freely filtered by the glomerulus and is not secreted but is fully reabsorbed and broken down by the renal tubules. Therefore, Cystatin C concentrations indicate a stronger correlation with GFR (glomerular filtration rate), increase with the decrease of GFR than that between creatinine and GFR. The most widely used measures of GFR in clinical practice are based on the 24-hour creatinine clearance or serum creatinine concentration. β2-microglobulin and serum creatinine are also measured as a marker of renal function for GFR. The measurement of creatinine clearance requires the inconvenience such as the difficulty and the burden for a patient by a timed urine collection, which may be incomplete for various reasons. Serum creatinine is influenced by multiple non-renal factors including diet, gender, muscle mass and tubular secretion which can result in an overestimation of GFR.ϐ2-microglobulin is influenced by pre-renal factors because ϐ2-microglobulin indicated high in patients with an autoimmune disease or a malignant tumor. Because Cystatin C is not influenced by pre-renal factors as above, Cystatin C has been proposed as a new sensitive endogenous marker of renal function for GFR. 

Technical specifications

Refer to the product Instruction-For-Use (IFU) for complete details.