A serum measure of renal function that is independent of age, sex, and lean muscle mass.
A low molecular weight protein found in all tissues of the body.
It is filtered at the glomerulus and not secreted into the renal tubules or absorbed into the bloodstream, and is not affected by muscle mass or diet.
A member of the cystatin family of proteins that bind and inhibit lysosomal cysteine proteases.
It has a low molecular weight in it composed of 120 amino acid residues and his synthesized continuously by all nucleated cells.
It is not protein bound in positively and is positively charge, allowing it to be freely filtered by the glomerulus.
Filtered cystatin C is primarily reabsorbed in the kidney proximal tubule where it is metabolized.
It is produced at a constant rate and freely filtered at the glomerulus.
It’s plasma levels are a measure of GFR.
Unlike creatinine plasma level levels of statin C are not affected by tissue muscle mass.
A stronger predictor of cardiovascular risk and death in elderly people compared to serum creatinine.
Has a stronger and more linear risk relationship than creatinine as a GFR filtration marker.
Serum measurements as a marker for kidney function is more sensitive than serum creatinine based estimates in an elderly population.
CysC has shown superiority over serum creatinine estimation of drug clearance, evaluation of kidney functions in patients with altered muscle mass, and may be superior to serum creatinine for early identification of acute kidney injury onset, and renal recovery.
Baseline levels are more strongly associated with cardiovascular events and all-cause mortality than estimated GFR levels.
Less affected by muscle mass and metabolism than creatinine, but is not more sensitive to detect acute kidney injury than serum creatinine.
Particularly useful for individuals with altered creatinine reduction and or metabolism such as extremely high or low body size or muscle mass, limb amputation, high-protein diet, use of creatinine supplements, or use of drugs affecting tubular secretion of creatinine.
In in older individuals serum cystatin C levels, an estimate of GFR, is linearly related to the risk of cardiovascular events, premature death, and decline in functional status.
Obesity, hypothyroidism, cigarette smoking, and the use of systemic corticosteroids are associated with higher cystatin C levels and cause estimated GFR to be lower than the actual GFR.
Its addition to creatinine measurements and calculating eGFR significantly improves the risk classification for death, cardiovascular disease and end-stage renal disease.
Cystatin level is a better way to estimate renal function than creatinine in patients with low muscle mass.
It is freely filtered, reabsorbed, and extensively catabolized by the renal tubule.
It is produced by all nucleated cells in distributed throughout the extracellular fluid.
Serum concentrations are less influenced by muscle mass and diet than creatinine.
Non-GFR factors that affect the serum concentration are not well understood, but include thyroid and glucocorticoid hormones, obesity, inflammation , and smoking.
An estimated GFR by cystatin value of at least 30% lower than estimated GFR by creatinine is associated with higher rates of mortality, cardiovascular events, and kidney failure with replacement therapy.