Assesment of Renal Function

Glomerular Filtration Rate•Product of the average filtration rate of each nephron,

•Normal: 130 ml/min/1.73 m2 (men) &120 ml/min/1.73 m2 (women) varied with age, gender, body size, physical activity, diet, pharmacotherapy, & physiologic states.

•GFR: adjusted for body surface area (BSA), expressed per 1.73 m2 BSA

•Cannot be measured directly, measured as the urinary clearance of an ideal filtration marker.

Concept of Clearance•volume of plasma cleared of a marker by excretion per unit of time.

•The clearance of substance x (Cx) = Ax/Px,

•The value for clearance is related to the efficiency of elimination