Determination of glomerular function in advanced renal failure.

Abstract

suremmARY In 15 children with advanced chronic renal failure, glomerular filtration rate was determined by different methods. Inulin clearance correlated well with the mean of creatinine and urea clearance, and also with 51-chromium edetic acid (EDTA) clearance measured over 24 hours. The absolute values of creatinine clearance and of 51Cr-EDTA clearance measured up to 8 hours were higher than inulin clearance. In advanced renal failure both the 5'Cr-EDTA clearance measured over 24 hours, and the mean of creatinine and urea clearance, provide acceptable estimates of true glomerular filtration rate.

Glomerular Filtration Rate in Children with Advanced Chronic Renal Failure: Methods of Determination and Clinical Applications

“…Creatinine clearance [23] consistently exceeds and urea clearance falls short of inulin clearance. How ever, after chronic renal insufficiency has become ad vanced, with glomerular filtration rates less than 20 ml/min/1.73 m2, the mean of the sum of the creati nine and the urea clearances closely approximates inulin clearance in both adults [43] and children [45].…”

“…The slope of a plot of reciprocal values of plasma creatinine versus time provides a reasonable estimate of the rate of deteri oration of renal function as well as the effects of various therapeutic maneuvers. The correlation between inulin clearance and the reciprocal values of plasma creatinine is not satisfactory [45], but for practical purposes, serial measurements of plasma creatinine concentrations per mit the progression of renal failure to be monitored con veniently.…”

“…In the 'long' technique, plasma samples are taken at 5-min intervals from 5 to 60 min and then at 24 h. The 'long' technique correlates better than does the 'short' technique [45] in children with advanced chronic renal failure. Although the corre lation between 5lCr-EDTA and inulin clearance ap proaches 1 in both normal children and those with chronic renal disease ( fig.…”

“…Although the correlation of serum creatinine reciprocals with actual inulin clearance is not satisfactory, the serial trends of the two are con gruent. and the correlation itself can be improved to about 0.80 if a height correction is applied [45]: (height in cm X 0.43)/plasma creatinine in mg/dl.…”

“…Its value has been established in noncatheterized children with inulin clearances below 16 ml/min ( fig. 2) after 12-or 24-hour urine collections [41,45], although some con cern still lingers regarding its more widespread applica tion [27b, 35].…”