Comparison between Total and Renal Plasma Clearance of [51Cr]EDTA

Abstract

The total plasma (Et) and renal plasma (Er) clearances of 51Cr-EDTA were measured simultaneously in 40 patients with a wide range of renal function. The regression equation was Et = 0.997 Er + 4.1; the slope of the regression line was not significantly different from 1.00 and the intercept differed significantly from zero. Independent of renal function, 51Cr-EDTA has a significant extrarenal clearance of approximately 4 ml/min. The data are used to correct the total 51Cr-EDTA plasma clearance, measured by a simplified method, to yield a rapid, accurate and precise measurement of glomerular filtration rate for routine clinical use.