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Updated: Jun 18, 2026
Physiology Lab Demonstration: Glomerular Filtration Rate in a Rat
Published on: July 26, 2015
Development of a beta-trace protein based formula for estimation of glomerular filtration rate
Amina Benlamri1, Renisha Nadarajah, Abeer Yasin
1Department of Paediatrics, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada.
Insights
A new formula using Beta-trace protein (BTP) estimates glomerular filtration rate (GFR) in children more accurately than the Schwartz formula. This novel method improves pediatric GFR calculation for better kidney function assessment.
Area of Science:
- Nephrology
- Pediatric Medicine
- Biomarker Research
Background:
- Glomerular filtration rate (GFR) is a key indicator of kidney function.
- Current GFR estimation formulas in children, like the Schwartz formula, have limitations.
- Beta-trace protein (BTP) has emerged as a potential novel marker for GFR assessment.
Purpose of the Study:
- To develop and validate a novel pediatric formula for estimating GFR using Beta-trace protein (BTP).
- To compare the accuracy and precision of the BTP-based GFR formula against the established Schwartz formula in children.
Main Methods:
- GFR, serum creatinine, and BTP levels were measured in 387 children undergoing renal scans.
- A stepwise linear regression analysis was used to derive a BTP-based GFR estimation formula.
- The novel formula was validated in a separate control group of 99 children.
Main Results:
- The BTP-derived GFR estimate showed a strong correlation with measured GFR (r=0.80), outperforming the Schwartz formula (r=0.70).
- Bland-Altman analysis indicated comparable mean bias between the BTP formula and the Schwartz formula.
- The BTP-based formula demonstrated a higher percentage of values within 10% and 30% deviation compared to the Schwartz formula.
Conclusions:
- A novel, accurate, and precise formula for estimating GFR in children using Beta-trace protein (BTP) has been developed.
- This BTP-based formula offers improved accuracy over the traditional Schwartz formula for pediatric GFR estimation.
- Gender-specific formulas did not enhance estimation accuracy, suggesting a single pediatric formula is effective.
Abstract:
Beta-trace protein (BTP) is a novel marker of glomerular filtration rate (GFR). To date, no pediatric formula for calculating GFR based on BTP has been developed. We measured GFR, serum creatinine and BTP in 387 children who underwent 474 (99m)Tc-diethylene triamine pentaacetic acid renal scans. A BTP-based formula for estimating GFR was derived using stepwise linear regression analysis. A separate control group of 116 measurements in 99 children was used to validate the novel formula. A formula was also developed for each gender. The novel formula is: [formula: see text]. The Spearman rank correlation coefficient between the BTP-derived GFR estimate and the measured GFR was 0.80 [95% confidence interval (CI) 0.76-0.83], which is substantially better than that derived with the Schwartz formula (r = 0.70, 95% CI 0.65-0.74). The Bland-Altman analysis revealed a mean bias of 1.21% [standard deviation (SD) 28%] in the formula development dataset, which was virtually identical to the 1.03% mean bias (29.5% SD) in the validation group and no different from the Schwartz formula bias. The percentage of values within 10% (33.0 vs. 28.3%) and 30% deviation (76.8 vs. 72.6%) were better for BTP-based formula than for the Schwartz formula. Separate formulas according to gender did not perform better than that for the pediatric population. This BTP-based formula was found to estimate GFR with reasonable precision and provided improved accuracy over the Schwartz GFR formula.
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