Role of renal functional reserve in pediatrics

Renal functional reserve (RFR) has been measured in 14 RFR studies on 12 pediatric patients. These children had evidence of a decrease in the number of nephrons due to upper urinary tract damage or absence of one kidney. The studies were done because the children were considered at risk for glomerular hyperfiltration in the absence of evidence of chronic kidney disease. They had normal serum electrolytes, normal urinalyses and glomerular filtration rates above 60 ml/min/1.73 m(2). Seven studies showed an absence of glomerular hyperfiltration, two studies confirmed glomerular hyperfilration and one study fell into the "questionable" range for glomerular hyperfiltration. The study was technically unsatisfactory in four instances, two of which were in children with gross anatomic abnormalities. The report illustrates the use of RFR in evaluation of children in a pediatric renal clinic.