A Study on urine concentrating function and its changes by aging, and comparison of urine specific gravity by refractometer and osmolality was done in 183 neonates and children who were admitted at the department of pediatrics, Korea university
hospital
from march 1991 to May 1991.
Urine specificity was measured by refractometer and urine osmolality was measured by osmometer using a freezing point.
@ES The results were as follows:
@EN 1) Urine specific gravity and urine osmolality were increased by aging, but after 7 years old, this tendency was not noted definitly.
2) Specific gravity and osmolallty correlated strongly in each age groups. But correlation in the neonates relatively decreased than in older children aged from 1 months to 12 years old. And also the slope of all regression lines were different.
The
calculated equation for the slope of the regression line was 23.3X in the neonates, 26.9X in the infants, and 42.2X, 35.1X, 37.6X, 33.5X in the older children.
In conclusion, we suggest that the concentrating ability of the kidney is almost matured about 7~9 years old. And in infant, especially neonatal period, osmolality is the only accurate measure of urine concentration in the neonates.
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