Related Experiment Video
Updated: Feb 2, 2026
Transdermal Measurement of Glomerular Filtration Rate in Mice
Published on: October 21, 2018
Comparison of high glomerular filtration rate thresholds for identifying hyperfiltration
Harini A Chakkera1, Aleksandar Denic2, Walter K Kremers3
1Division of Nephrology and Hypertension, Mayo Clinic, Scottsdale, AZ, USA.
Insights
High glomerular filtration rate (GFR) can indicate hyperfiltration, but the best definition remains unclear. Age-based uncorrected measured GFR (mGFR) best reflects hyperfiltration but cannot distinguish it from a high nephron number.
Area of Science:
- Nephrology
- Renal Physiology
- Kidney Disease Research
Background:
- High glomerular filtration rate (GFR) is frequently utilized as a proxy for single-nephron hyperfiltration.
- The precise definition of high GFR that accurately represents the clinical and structural aspects of hyperfiltration requires clarification.
Purpose of the Study:
- To identify the definition of high GFR that best correlates with the clinical and structural characteristics of hyperfiltration.
- To evaluate different GFR measurement and estimation methods for their ability to identify hyperfiltration.
Main Methods:
- Living kidney donors were evaluated using measured GFR (mGFR) via iothalamate clearance and estimated GFR (eGFR) via the CKD-EPI equation.
- High GFR was defined using the 95th percentile, with both overall and age-specific thresholds, and GFR values were corrected or uncorrected for body surface area.
- Associations between high GFR definitions and clinical characteristics, kidney volume, and, in donors, biopsy findings (nephron number, glomerular volume) and single-nephron GFR were analyzed.
Main Results:
- The 95th percentile for corrected mGFR was 134 mL/min/1.73 m², and for eGFR was 118 mL/min/1.73 m².
- Age-based thresholds varied by GFR measurement method and correction status.
- High age-based uncorrected mGFR demonstrated the strongest associations with indicators of hyperfiltration, including higher single-nephron GFR, larger glomerular and kidney volumes, and increased urinary albumin, but also correlated with a higher nephron number.
Conclusions:
- High age-based uncorrected measured GFR (mGFR) most consistently reflects hyperfiltration.
- However, this definition has limitations in clinical utility as it does not differentiate between hyperfiltration and an increased number of nephrons.
Background:
High glomerular filtration rate (GFR) is often used as a surrogate for single-nephron hyperfiltration. Our objective was to determine the definition for high GFR that best reflects clinical and structural characteristics of hyperfiltration.
Methods:
We studied living kidney donors at the Mayo Clinic and Cleveland Clinic. Potential donors underwent evaluations that included measured GFR (mGFR) by iothalamate clearance and estimated GFR (eGFR) by the serum creatinine-based Chronic Kidney Disease-Epidemiology collaboration (CKD-EPI) equation. High GFR was defined by the 95th percentile for each method (mGFR or eGFR) using either overall or age-specific thresholds. High mGFR was defined as both corrected and uncorrected for body surface area. The association of high GFR by each definition with clinical characteristics and radiologic findings (kidney volume) was assessed. In the subset that donated, the association of high GFR with kidney biopsy findings (nephron number and glomerular volume) and single-nephron GFR was assessed.
Results:
We studied 3317 potential donors, including 2125 actual donors. The overall 95th percentile for corrected mGFR was 134 mL/min/1.73 m2 and for eGFR was 118 mL/min/1.73 m2. The age-based threshold for uncorrected mGFR was 198 mL/min - 0.943×Age, for corrected mGFR it was 164 mL/min/1.73 m2 - 0.730×Age and for eGFR it was 146 mL/min/1.73 m2 - 0.813×Age. High age-based uncorrected mGFR had the strongest associations with higher single-nephron GFR, larger glomerular volume, larger kidney volume, male gender, higher body mass index and higher 24-h urine albumin, but also had the strongest association with high nephron number. A high age-height-gender-based uncorrected mGFR definition performed almost as well but had a weaker association with nephron number and did not associate with male gender.
Conclusions:
High age-based uncorrected mGFR showed the most consistent associations reflective of hyperfiltration. However, high age-based uncorrected mGFR has limited clinical utility because it does not distinguish between hyperfiltration and high nephron number.
Related Concept Videos
01:28Glomerular Filtration Rate and its Regulation
GFR regulation involves two primary intrinsic controls: the myogenic and tubuloglomerular feedback mechanisms.
The myogenic...
01:15Glomerular Filtration
Components of the Filtration Membrane
The filtration process involves three key layers: the glomerular endothelial cells, the basement membrane, and the podocyte-formed filtration slits.
01:26Glomerular Filtration: Net Filtration Pressure
GBHP, with an average value of 55 mmHg, promotes filtration by pushing water and solutes through the filtration membrane. This is balanced by two opposing forces: CHP, a "back pressure" exerted against the filtration membrane by fluid already in the capsular space and renal...
01:02Renal Drug Excretion: Glomerular Filtration
Drugs gain access to the kidney via the renal artery, which progressively branches off into afferent arterioles....
01:28Drug Dosing in Renal Diseases: Estimation of Glomerular Filtration Rate Based on Serum Creatinine Concentration
01:17Drug Elimination by Renal Route: Glomerular Filtration