Caspian Journal of Pediatrics

Background: Due to difficulty of obtaining a 24h urine (especially in children), a random urine calcium sample is recommended to detect of hypercalciuria. However, recent studies have shown that the urinary calcium/creatinine ratio varies with age and geographic areas. So, the aim of this study was determining the normal value of urinary calcium to creatinine ratio in healthy adolescent’s children.

Methods: Four hundred eight children of 12 to 14-year-old were randomly selected from middle school in Babol (north of Iran) and early morning urinary samples of them were studied for determining normal urine Ca/Cr, Na/Cr and K/Cr ratios. Children who had the family with the history of renal disease were excluded from this study.

Results: In this study the 50% and 95% of urinary Ca/Cr ratio were 0.08±0.02 and 0.13 mg/mg for the whole group. The mean of urinary Ca/Cr ratio in boys and girls were 0.08±0.03 and 0.08±0.02, respectively. The mean of urinary Na/Cr ratio in boys was 1.4±0.48 and in girls was 1.21±0.33. Also, the mean of urinary K/Cr ratio in boys and girls were 0.30±0.11 and 0.29±0.10, respectively.

Conclusions: This study was shown that the urinary Ca/Cr ratio of these children is different from other geographic areas. Also, a direct relationship was seen between urinary Ca/Cr ratio, Na/Cr and k/Cr ratios.