Measurement of kidney function.

Accurate estimation of kidney function is central to the detection, evaluation, and treatment of chronic kidney disease (CKD). Glomerular filtration rate (GFR) is widely accepted as the best overall measure of kidney function and as such it forms the basis of definition and classification system for CKD. GFR cannot be measured directly in clinical practice and multiple methods are used to estimate GFR, all of which have their strengths and limitations. The current recommended method is to use estimating equations based on serum creatinine and which incorporate demographic and clinical variables.