Homocysteine, often shortened to HCY, is a thiol containing amino acid produced by the intracellular demethylation of methionine. Excess HCY in the bloodstream may cause injuries to arterial vessels due to its irritant nature and result in inflammation and plaque formation, which may eventually cause a blockage of blood flow to the heart.

Serum Cystatin C(Cys-C) has been proposed as a marker of glomerular filtration rate(GFR). Serum creatinine (creatinine) is widely used to estimate the glomerular filtration rate, but its tubular secretion, dependence on muscle mass, alteration in some inflammatory diseases, and analytical interferences can limit its utility. Thus, Cys-C has been proposed as a novel biomarker of kidney function.