Electrolyte measurements differ between point-of-care and reference analysers in dogs with hypoadrenocorticism

Area of Science:

• Veterinary Medicine
• Clinical Pathology
• Canine Endocrinology

Background:

• Hypoadrenocorticism (Addison's disease) in dogs requires regular blood electrolyte monitoring.
• Point-of-care (POC) analyzers are commonly used for rapid electrolyte analysis in clinical practice.
• Medication dosages are adjusted based on POC electrolyte results.

Purpose of the Study:

• To evaluate the accuracy of two POC analyzers (IDEXX Catalyst Dx, IDEXX VetStat) against a reference laboratory method.
• To assess the measurement of sodium, potassium, chloride, and sodium:potassium ratios in dogs with hypoadrenocorticism.
• To investigate potential clinical implications of inaccurate POC electrolyte measurements.

Main Methods:

• Prospective cross-sectional study involving 48 dogs with hypoadrenocorticism.
• Paired blood samples analyzed on two POC analyzers and a reference laboratory.
• Statistical analysis using Bland-Altman and Passing-Bablok regression.

Main Results:

• Both POC analyzers demonstrated bias compared to the reference method.
• Poor agreement was observed for sodium and chloride concentrations.
• Analyzers generally reported higher electrolyte values than the reference method, except for VetStat's potassium readings.

Conclusions:

• Significant differences exist between POC analyzers and reference laboratory methods for electrolyte measurement in hypoadrenocorticism cases.
• Clinical relevance of these discrepancies warrants further investigation.