Renal function and laboratory evaluation

This paper reviews the normal renal function in relation to common functional tests helpful to detect nephrotoxicity. The measurement of renal blood flow, intrarenal distribution of blood flow, and glomerular filtration rate remain the basic parameters of nephrotoxicity. Renal tubular function is accurately measured by standard clearance tests for solutes including electrolytes, glucose and amino acids. The renal concentrating capacity serves as a sensitive but non-specific measure of renal integrity. The measurement of plasma concentration of some solutes is helpful to identify nephrotoxicity, but is most effective when a profile of solutes is measured over a time period. Urinary protein excretion and particularly the excretion of enzymes may localize the nephrotoxicity in certain tubular segments. Due to the multiple functions of the kidney, no single test or group of tests can be relied upon to detect nephrotoxicity. A battery of tests including screening tests and specific tests to measure glomerular or tubular function must be selected to match the pattern of nephrotoxicity.