RESUMEN
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.
Asunto(s)
Estatura , Creatinina/sangre , Tasa de Filtración Glomerular , Adolescente , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Matemática , Sensibilidad y EspecificidadRESUMEN
In children and adolescents the evaluation of proteinuria is cumbersome because of the need to obtain timed urine collections. The protein/creatinine ratio (using a Coomassie blue binding technique and a kinetic Jaffe reaction, respectively) measured in 134 pediatric patients with renal disease aged 2 months to 16 years correlated closely with the overnight urine protein excretion rates using the statistical approach suggested by Bland and Altman to compare methods of measuring some quantity. The upper limit of urinary protein/creatinine ratio measured in 252 healthy children and adolescents aged 4 to 19 years was shown to be 19 mg/mmol. No age-related differences in urinary protein excretion were noted in healthy subjects. The random urine protein/creatinine ratio provides an accurate assessment of quantitative protein excretion and avoids errors and difficulties associated with timed urine collection.