October 1992

Serum Creatinine Level and Renal Function in Children

Author Affiliations

From the Division of Nephrology and Children's Kidney Center, Children's Hospital of Buffalo (NY), and the Departments of Pediatrics (Drs Springate and Feld) and Radiology (Dr Christensen), School of Medicine and Biomedical Sciences, State University of New York at Buffalo.

Am J Dis Child. 1992;146(10):1232-1235. doi:10.1001/archpedi.1992.02160220118036

• Objective.  —To evaluate the accuracy of serum creatinine and height/serum creatinine glomerular filtration rate (CrGFR) formula as screening tests for abnormal renal function defined by plasma diethylenetriaminepenta-acetic acid (DTPA) clearance.

Design.  —Patient series.

Setting.  —The Children's Hospital of Buffalo (NY).

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

Measurements.  —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, <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, <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.(AJDC. 1992;146:1232-1235)