Measuring and estimating glomerular filtration rate in children

Area of Science:

• Nephrology
• Clinical Chemistry
• Pharmacokinetics

Background:

• Glomerular filtration rate (GFR) is the primary indicator of kidney function.
• Accurate GFR measurement is vital for diagnosing kidney disease, monitoring progression, and optimizing drug dosages.
• While inulin clearance is the gold standard, practical clinical measurements often use other exogenous markers or estimations.

Purpose of the Study:

• To review methods for measuring GFR using renal and plasma clearance.
• To discuss the application and limitations of estimated GFR (eGFR) equations.
• To provide guidance on the appropriate use of eGFR equations in children.

Main Methods:

• Explanation of renal clearance and plasma clearance techniques for GFR measurement.
• Discussion of protocols for determining the area under the plasma disappearance curve.
• Review of commonly used eGFR equations based on serum creatinine or cystatin C and demographic data.

Main Results:

• Inulin clearance is the gold standard but not always practical.
• Plasma clearance of exogenous markers offers an alternative measurement.
• eGFR equations provide convenient estimations but require careful application due to inherent limitations.

Conclusions:

• Understanding GFR measurement techniques is crucial for accurate kidney function assessment.
• eGFR equations are valuable tools but their accuracy depends on correct usage and patient population.
• This review aims to clarify the application of GFR measurement and estimation methods in clinical settings, particularly for pediatric patients.