BUN: Creatinine Ratio - Definition of the Normal Range in Children

Abstract

The normal range for the BUN:Creatinine ratio (BCR) has not been determined for infants and children. The objectives of this study were to: i) test the hypothesis that the BCR is higher in young children, and ii) establish normal BCR ranges for children of various ages. In this retrospective single-center review, 482 patients evaluated in an ambulatory setting were studied. The mean BCR declined significantly with age (P<0.0001). There was an inverse relationship between BCR and age, body mass index (BMI), and serum creatinine and a direct relationship with BUN and estimated glomerular filtration rate. Based on our findings, we concluded that BCR values in adult patients are inapplicable to children below 10 years of age. We suggest that BCR greater than 60 in children 10 years of age or younger, and greater than 30 in children older than 10 years be considered abnormal. Application of age-specific pediatric criteria will ensure the proper application of the BCR in evaluating acutely ill children.