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Serum creatinine level and renal function in children
J E Springate1, S L Christensen, L G Feld
1Division of Nephrology, Children's Hospital of Buffalo, NY.
Insights
The height/serum creatinine glomerular filtration rate (Cr-GFR) formula accurately screens for abnormal kidney function in children. This method is more effective than serum creatinine alone for detecting renal insufficiency and failure.
Area of Science:
- Pediatric Nephrology
- Diagnostic Accuracy
- Renal Function Testing
Background:
- Abnormal renal function in children requires accurate screening methods.
- Serum creatinine levels and the height/serum creatinine glomerular filtration rate (Cr-GFR) formula are potential screening tools.
Purpose of the Study:
- To compare the accuracy of serum creatinine and the Cr-GFR formula in identifying impaired renal function in pediatric patients.
Main Methods:
- Evaluated 87 pediatric patients (ages 2-20) using plasma diethylenetriaminepenta-acetic acid (DTPA) clearance as the reference standard.
- Calculated Cr-GFR using the formula: GFR = kL/serum creatinine.
Main Results:
- The Cr-GFR formula demonstrated high sensitivity (95%) and specificity (93%) for detecting impaired renal function (DTPA clearance < 80 mL/min/1.73 m2).
- The Cr-GFR formula identified 91% of children with renal insufficiency (DTPA clearance 40-79 mL/min/1.73 m2), compared to 65% with elevated serum creatinine.
- The Cr-GFR formula showed superior specificity (100%) compared to serum creatinine (75%) in identifying renal failure (DTPA clearance < 40 mL/min/1.73 m2).
Conclusions:
- The Cr-GFR formula is a more accurate and reliable screening test for estimating glomerular filtration rate (GFR) in children than serum creatinine alone.
- The Cr-GFR formula offers a simple and effective method for assessing the presence and severity of impaired renal function in pediatric populations.
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.
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, 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.