The role of the laboratory in evaluation of kidney function

Evaluation of kidney function by physical examination alone is imprecise and limited. Quantitative, reproducible assessment of kidney function required laboratory measurements of substances in plasma and urine, followed by reliable interpretation. Thus, glomerular filtration, urine protein excretion, water metabolism, and electrolyte disturbances may be quantified. These data are very useful in the single and serial assessment of patients with kidney disease and in evaluation of the effects of treatment.