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Updated: Jan 17, 2026
Physiology Lab Demonstration: Glomerular Filtration Rate in a Rat
Published on: July 26, 2015
Comparison of different equations for estimating the glomerular filtration rate in pediatric kidney transplant
Paphawadee Sukboonthong1, Julaporn Pooliam2, Maturin Jantongsree3
1Department of Pediatrics, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand.
Insights
The Schwartz-Lyon equation is most accurate for estimating kidney function in pediatric kidney transplant recipients. For optimal results, consider the U25 plasma creatinine-cystatin C equation when cystatin C measurements are available.
Area of Science:
- Pediatric Nephrology
- Transplant Medicine
- Clinical Chemistry
Background:
- Accurate estimation of glomerular filtration rate (eGFR) is critical for managing pediatric kidney transplant recipients.
- The choice between pediatric and adult-specific plasma creatinine (PCr)-based formulas is complex due to physiological differences in pediatric patients receiving adult donor kidneys.
Purpose of the Study:
- To evaluate the performance of various pediatric and adult PCr-based equations for eGFR estimation in pediatric kidney transplant recipients.
- To identify the most accurate eGFR equation for this specific patient population.
Main Methods:
- Cross-sectional study of pediatric kidney transplant recipients (ages 1-18) who received adult donor kidneys.
- Comparison of multiple PCr-based GFR equations against the CKiD 2012 combined PCr-CystC equation using ICC, CCC, TDI, P30, Bland-Altman plots, and ROC analysis.
- Evaluation of the correlation between the U25 PCr-CystC and the reference CKiD 2012 equation.
Main Results:
- The Schwartz-Lyon equation showed the highest performance (ICC=0.913, CCC=0.911, P30=99.2%) among PCr-based equations.
- Other equations like U25, FAS-height, and Bedside Schwartz demonstrated comparable performance.
- The U25 PCr-CystC equation exhibited excellent agreement with the reference equation (ICC=0.993, CCC=0.990, P30=100%).
- Optimal agreement thresholds were identified for each equation, beyond which bias increased.
- Better performance was observed in patients aged 10-18 years.
Conclusions:
- The Schwartz-Lyon equation is the top-performing PCr-based method for eGFR estimation in pediatric kidney transplant recipients, especially when eGFR < 70 mL/min/1.73 m² and in older children (10-18 years).
- The U25 PCr-CystC equation offers the best overall agreement and is recommended when cystatin C measurement is feasible.
Background:
Accurate glomerular filtration rate estimation (eGFR) is essential for managing pediatric kidney transplant recipients. Given the physiology of pediatric patients receiving adult-donor kidneys, identifying the most appropriate plasma creatinine (PCr)-based formula-pediatric or adult-specific-is crucial.
Methods:
This cross-sectional study included pediatric kidney transplant recipients (age 1-18 years) who received adult-donor kidneys. We compared agreement thresholds of various pediatric and adult PCr-based GFR equations with CKiD 2012 combined PCr‒cystatin C (PCr-CystC) equation via intraclass correlation coefficients (ICCs), concordance correlation coefficients (CCCs), total deviation index (TDI), P30 performance metric (P30), Bland-Altman plots, and receiver-operating characteristic (ROC) analysis. Correlation between CKiD under 25 (U25) PCr-CystC and reference CKiD 2012 equation was also evaluated.
Results:
One hundred twenty samples were collected from 23 recipients (mean age = 14.2 ± 3.4 years) and donors (mean age = 31.7 ± 10.0 years). Schwartz-Lyon equation demonstrated the highest performance with the reference (ICC = 0.913, CCC = 0.911, TDI = 14.0 mL/min/1.73 m2, P30 = 99.2%). U25 (ICC = 0.922, CCC = 0.882, P30 = 93.3%), full age spectrum (FAS)-height (ICC = 0.897, CCC = 0.877, P30 = 96.7%), and Bedside Schwartz equations (ICC = 0.850, CCC = 0.819, P30 = 89.2%) showed comparable performance. Bland-Altman plots revealed proportional bias (p < 0.05), leading to ROC analysis, which identified eGFR < 70 mL/min/1.73 m2 for Schwartz-Lyon, U25, and FAS-height, and < 60 mL/min/1.73 m2 for Bedside Schwartz as optimal agreement thresholds, beyond which each equation showed increased bias. Subgroup analyses also showed better performance in patients aged 10-18 years. Additionally, U25 PCr-CystC equation showed excellent agreement with the reference (ICC = 0.993, CCC = 0.990, P30 = 100%).
Conclusions:
Schwartz-Lyon equation demonstrated the highest performance among PCr-based equations with the reference in pediatric kidney transplant recipients, particularly when eGFR was < 70 mL/min/1.73 m2 and in patients aged 10-18 years. U25 PCr-CystC equation showed best overall agreement with the reference and should be preferred where CystC measurement is feasible.
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