Comparison of Electrolytes and Hemoglobin Testing Between a Blood Gas Analyzer and Core Lab Analyzers

Area of Science:

• Clinical Chemistry
• Point-of-Care Testing
• Laboratory Medicine

Background:

• Blood gas analyzers (BGAs) are essential for emergency department (ED) point-of-care testing.
• Uncertainty exists regarding the agreement of BGA results with core laboratory analyzers for electrolytes and hemoglobin.
• This study aims to compare BGA and core lab results for critical analytes and assess BGA turnaround time (TAT).

Purpose of the Study:

• To evaluate the interchangeability of hemoglobin (Hb) and electrolyte measurements between a BGA and core laboratory analyzers.
• To compare the turnaround time (TAT) of BGAs versus core laboratory analyzers in an emergency department setting.
• To assess the clinical utility of BGAs for time-sensitive patient care in the ED.

Main Methods:

• A retrospective analysis of 139 ED patients was conducted.
• Potassium (K+), sodium (Na+), chloride (Cl-), Hb, and hematocrit (Hct) were compared between the GEM4000 BGA and core lab analyzers (Sysmex XN3000, Canon TBA-FX8).
• Interchangeability was assessed using a three-step protocol based on Clinical Laboratory Improvement Amendments (CLIA) criteria.

Main Results:

• Significant discrepancies were observed between the GEM4000 BGA and core laboratory results.
• Chloride (Cl-) and potassium (K+) showed good interchangeability; hemoglobin (Hb) showed moderate interchangeability.
• Sodium (Na+) and hematocrit (Hct) exhibited poor interchangeability, while the GEM4000 demonstrated significantly faster TAT compared to core labs.

Conclusions:

• The GEM4000 BGA improves ED care timeliness but exhibits variable interchangeability with core laboratory results.
• Clinical context is crucial for interpreting Na+ and Hct results, especially when discrepancies arise.
• Reviewing pre-analytical handling of BGA specimens is recommended to address potential Hb and Hct measurement errors.