Real-time Measurement of Glomerular Filtration Rate

Author(s): Richard Solomon

Glomerular filtration rate (GFR) is the most widely used metric of kidney function. The search for an ideal marker of glomerular filtration was ultimately resolved by Homer Smith and his colleagues with the introduction of inulin (1). For many years, inulin clearance was considered the gold standard for measurement of GFR but was not practical for clinical medicine. Creatinine was adopted as a surrogate serum marker of GFR and in the past 15 years, equations utilizing serum creatinine, age, gender, and race were developed to estimate GFR in the steady state (2).