[Plasma creatinine, and clearance and urinary excretion of creatinine in children]

The 24 hour clearance of endogenous creatinine was compared with that of inulin in 112 children aged between 15 months and 17 years. The children had a variety of kidney disorders with renal function than ranged from normal to terminal renal failure. When the inulin clearance was less than 10 ml/min/1.73 m2 it was on average 75% of the value of the creatinine clearance. Between 10 and 60 ml/min/1.73 m2 the relationship of the inulin clearance to that of creatinine was similar (77%) but above 60 ml/min/1.73 m2 the ratio of the inulin clearance to that of creatinine was 1.05 with a wide scatter. With increasing degrees of renal failure the plasma creatinine increased less in the children under 2 years old than in those over this age so it is poor index of glomerular function in infants. In renal failure the urinary excretion of creatinine in 24 hours was reduced. When the clearance was less than 10 ml/min/1.73 m2, the urinary creatinine excretion for children under the age of 2 was 58% of the normal for the age and for children over 2, it was 86% of the expected mean.