Trueness assessment of routine electrolytes measuring systems using the candidate reference method by ion...

Area of Science:

• Clinical Chemistry
• Analytical Chemistry
• Laboratory Medicine

Background:

• Serum electrolytes (sodium, potassium, magnesium, calcium) are vital clinical analytes.
• Standardization of electrolyte detection is crucial for accurate patient diagnosis.
• Routine analytical systems require validated reference methods for trueness assessment.

Purpose of the Study:

• To develop and evaluate an inexpensive candidate reference method for serum electrolyte measurement.
• To assess the trueness of routine analytical systems for four key cations.
• To promote standardization in clinical laboratory electrolyte detection.

Main Methods:

• Development of an ion chromatography (IC) method using Cesium as an internal standard.
• Evaluation of the IC method using human serum pools and NIST SRM 956c.
• Comparison of the IC method with five routine analytical systems using clinical samples.

Main Results:

• High recovery rates for sodium (99.69%), potassium (100.34%), magnesium (100.43%), and calcium (99.89%).
• Excellent precision (intra-batch SD & intra-laboratory precision <1%) for all four ions.
• Routine systems showed good concordance with the IC method, meeting quality specifications for potassium and magnesium.

Conclusions:

• The developed IC method is simple, practical, accurate, and precise.
• The IC method serves as a reliable candidate reference method for serum electrolytes.
• Routine electrolyte measurement systems demonstrate acceptable bias and good concordance with the reference method.