Limitations concerning the use in children of the relationship between plasma creatinine and body height to derive glomerular filtration rate.

The value of the formula, (Formula: see text) was assessed over a two-year period in 314 children aged 1 month to 17 years by comparing simultaneously determined 51Cr EDTA slope clearance and plasma creatinine measurements, and in 225 children aged 1 month to 16 years comparing with duplicate short-term creatinine clearance determinations. The relationship with 51Cr EDTA slope clearance is best in patients over the age of 3 years with clearance rates below 60 ml. min-1/1.73m2 but even so is subject to doubt over a wide range. The relationship with creatinine clearance shows less scatter at higher levels of clearance but the same doubt exists when it is used as an estimate of glomerular filtration rate.