Performance of enzymatic creatinine methods in the pediatric concentration range

Area of Science:

• Clinical Chemistry
• Biomarker Analysis
• Pediatric Medicine

Background:

• Creatinine is a key biomarker for assessing kidney function and glomerular filtration rate in both adults and children.
• Recent studies evaluating creatinine measurement performance specifically within the pediatric concentration range are limited.
• Accurate creatinine measurement is crucial for timely diagnosis and management of kidney diseases in pediatric populations.

Purpose of the Study:

• To assess the measurement performance of commonly used enzymatic creatinine assays on four different platforms (Abbott Alinity, Radiometer ABL800, Roche Cobas, Siemens Atellica) within the pediatric concentration range.
• To compare these platforms against the gold standard isotope dilution mass spectrometry (IDMS) reference method.
• To evaluate the performance of Roche enzymatic methods using control sera from the Nordic Association of Clinical Chemistry.

Main Methods:

• Comparative analytical study involving four automated immunoassay platforms.
• Measurement of creatinine concentrations in pediatric-relevant samples.
• Comparison of results against the isotope dilution mass spectrometry (IDMS) reference method.
• Utilized Nordic Association of Clinical Chemistry control sera for secondary method comparison.

Main Results:

• Significant variability in accuracy was observed among the evaluated creatinine methods at low concentration ranges relevant to pediatrics.
• The relative differences between measurement platforms decreased as creatinine concentration increased, particularly below 75 µmol/L.
• Applying a single absolute factor for method bias correction, as sometimes recommended, may compromise measurement accuracy in the pediatric creatinine range.

Conclusions:

• Current enzymatic creatinine assays exhibit variable performance in the pediatric concentration range.
• Standardization and improved agreement between creatinine measurement methods are necessary for reliable pediatric kidney function assessment.
• Manufacturers and stakeholders must consider the unique challenges of low-concentration creatinine measurements in pediatric patients when developing bias correction strategies.