[The estimated glomerular filtration rate in outpatients]

Area of Science:

• Nephrology
• Clinical Chemistry
• Medical Diagnostics

Background:

• Glomerular filtration rate (GFR) is a key indicator of kidney function.
• Accurate GFR estimation is crucial for diagnosing and managing chronic kidney disease.
• The Modification of Diet in Renal Disease (MDRD) formula is widely used for eGFR calculation.

Purpose of the Study:

• To evaluate the performance of the MDRD formula for eGFR estimation across different serum creatinine analytical systems.
• To identify potential biases and inaccuracies in eGFR calculations based on the analytical system used.

Main Methods:

• Serum creatinine concentrations were measured in adult outpatients using five distinct analytical systems: Abbott Architect, Roche Modular, Roche Integra 400, Roche Integra 700, and Roche Hitachi.
• The MDRD formula was applied to estimate GFR for each patient.
• Analytical performance, including total error (TE) and bias, was assessed for each system.

Main Results:

• Four of the five analytical systems demonstrated comparable GFR distributions.
• The Roche Hitachi system exhibited significantly higher TE and bias compared to acceptable requirements.
• Patients assessed using the Roche Hitachi system showed a twofold higher proportion of eGFR < 60 ml/min/1.73 m² compared to other systems.

Conclusions:

• The analytical system used for serum creatinine measurement significantly impacts eGFR estimation.
• The Roche Hitachi system demonstrated suboptimal performance, potentially leading to misclassification of kidney function.
• Ensuring analytical systems meet established quality requirements is essential for reliable clinical use of eGFR estimates.