Serum creatinine level and renal function in children.
OBJECTIVE
To evaluate the accuracy of serum creatinine and height/serum creatinine glomerular filtration rate (Cr-GFR) formula as screening tests for abnormal renal function defined by plasma diethylenetriaminepenta-acetic acid (DTPA) clearance.


METHODS
Patient series.


METHODS
The Children's Hospital of Buffalo (NY).


METHODS
Eighty-seven consecutive patients ranging in age from 2 to 20 years.


METHODS
The Cr-GFR was calculated by means of the formula GFR (milliliters per minute per 1.73 m2) = kL/serum creatinine (milligrams per deciliter), where L is body length in centimeters and k is a constant dependent on age and sex. Plasma clearance of technetium Tc 99m-labeled DTPA was our reference method for determination of GFR (DTPA-GFR).


RESULTS
The Cr-GFR formula identified children with impaired renal function (DTPA clearance, less than 80 mL/min per 1.73 m2) with a sensitivity of 95% and a specificity of 93%. In contrast, the sensitivity and specificity of elevated serum creatinine level for this purpose were 80% and 96%, respectively. Of the children with renal insufficiency (DTPA clearance, 40 to 79 mL/min per 1.73 m2), 91% were correctly identified by the Cr-GFR formula. However, only 65% of these children had elevated serum creatinine levels. Although all children with renal failure (DTPA clearance, less than 40 mL/min per 1.73 m2) had abnormally high serum creatinine levels, the specificity of this test was significantly lower than that of the Cr-GFR formula (75% vs 100%, respectively).


CONCLUSIONS
The Cr-GFR formula is superior to serum creatinine level for estimating GFR. This formula provides a simple, reasonably accurate screening test for the presence and severity of impaired renal function.
Springate
J E
JE
Division of Nephrology, Children's Hospital of Buffalo, NY.
Christensen
S L
SL
Feld
L G
LG
D000293:Adolescent; D000328:Adult; D001827:Body Height; D002648:Child; D002675:Child, Preschool; D003404:Creatinine / Q000097:blood*; D005919:Glomerular Filtration Rate; D006776:Hospitals, Pediatric; D006801:Humans; D007674:Kidney Diseases / Q000097:blood* / Q000453:epidemiology / Q000378:metabolism; D008403:Mass Screening / Q000379:methods / Q000592:standards*; D008657:Metabolic Clearance Rate; D009518:New York / Q000453:epidemiology; D004369:Pentetic Acid / Q000378:metabolism / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D004369:Pentetic Acid; D003404:Creatinine