[Precision of glomerular filtration estimation by height/creatinine ratio in the child]

Formulae for estimating glomerular filtration rate with the use of body size, circulating creatinine, and an empirically derived constant are widely used. The aim of the present study was to determine whether these formulae enable accurate prediction of glomerular filtration measured from the labeled ethylenediaminetetraacetic acid in 843 pediatric patients. Bland-Altman analysis was performed on the measured glomerular filtration rate and that estimated using the constant developed in our laboratory. Age and sex of the 843 patients failed to consistently influence the empirically derived constant. Measured and estimated glomerular filtration rate were on the average identical. However, the 95% limits of agreement of the measured glomerular filtration rate with that estimated were wide (measured over estimated glomerular filtration from 0.53 to 2.04). Use of height to creatinine formulae to estimate glomerular filtration is therefore frequently insufficiently accurate.