Revisiting normal 51Cr-ethylenediaminetetraacetic acid clearance values in children

Purpose: Normal Cr-51-ethylenediaminetetraacetic acid ( EDTA) clearance values as a function of age were published a number of years ago. These values were based on data from children with a normal left to right ratio and a normal appearance on DMSA scintigraphy, despite the presence of an acute renal infection. At that time, the authors were unaware that hyperfiltration is a common phenomenon in patients with acute renal infection and that their normal values could have been significantly overestimated. The present work therefore aimed to re-appraise these normal values. Methods: In a first step, in order to verify the previous results, the same type of population was selected, namely patients with present or past urinary tract infection but normal images and a normal left to right ratio on DMSA scintigraphy. In a second step, the selection was based on patients who had had no recent urinary tract infection. In both series, a single blood sample method was used for the evaluation of Cr-51-EDTA clearance. Results: In the first group of patients, the results obtained were almost identical to those previously published. In the second group of patients, the results were significantly lower: after 2 years of age, the mean GFR value was 104 ml/min/ 1.73 m(2) ( 10th and 90th percentiles 81 and 135 ml/min/ 1.73 m(2), respectively), compared with 117 ml/ min/1.73 m(2) in the first group. Conclusion: The data of the second group are probably more representative of the true normal GFR values and can be applied to the entire paediatric population.