Estimated glomerular filtration rate (eGFR): A serum creatinine-based test for the detection of chronic kidney disease and its impact on clinical practice

Chronic kidney disease (CKD) is an important epidemic and public health problem that is associated with a significant risk for vascular disease and early cardiovascular mortality as well as progression of kidney disease. Currently it is classified into five stages based on the glomerular filtration rate (GFR) as recommended by many professional guidelines. Radiolabelled methods for measuring GFR are accurate but not practical and can be used only on a very limited scale while the traditional methods require timed urine collection with its drawback of inaccuracy, cumbersomeness and inconvenience for the patients. However, the development of formulabased calculation of estimated GFR (eGFR) has offered a very practical and easy approach for converting serum creatinine value into GFR result taking into consideration patient's age, sex, ethnicity and weight (depending on equation type). The commonly used equations include Cockraft and Gault (1976), Modification of Diet in Renal Disease (MDRD) (1999) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) (2009). It is the implementation of these equations particularly the MDRD that has raised the medical awareness in the diagnosis and management of CKD and its adoption by many guidelines in North America and Europe. The impact and pitfalls of each of these equations in the screening, diagnosis and management of patients with CKD are presented and discussed in this review.