Reference values of analytes in urine in the pediatric age

The detection of mineral metabolic disorders can explain several pathologies which require the comparison with reference values for their interpretation. The aim of this study was to determine the reference values of 470 Uruguayan school children with ages between 7 and 12 for sodium, potassium, calcium, magnesium, phosporous and urate and their relationship with creatinine in urine samples of the second urination of the morning. The median obtained were: Na/Crea: 139 mmol/g, K/Crea: 78 mmol/g, Ca/Crea: 77 mg/g, Mg/Crea: 71 mg/g, P/Crea: 500 mg/g, Ur/Crea: 554 mg/g, Crea: 117 mg/dL. A diminishment of excretion with the age was found, regardless the sex, except for Na/Crea and K/Crea. The values obtained were similar to those of others populations with a similar diet.