Interchangeability of blood gas, electrolyte and metabolite results measured with point-of-care, blood gas and core laboratory analyzers

Background: The random use of point-of-care, blood gas and core laboratory analyzers to measure electrolytes and metabolites increases the variability in test results. This study was designed to determine whether these results performed on whole blood (point-of-care and blood gas) and plasma (core laboratory) platforms are interchangeable without a risk of clinically relevant discrepancies. Methods: The interchangeability of the blood gas analysis, electrolytes, glucose, lactate and hemoglobin results performed with three stat platforms (i-STAT, Radiometer ABL 825, RapidLab 865) and two core laboratory platforms (Roche Modular P800 and Sysmex XE-2100) were evaluated using samples from critically ill patients. Results: For pH, pCO2, pO2 and Ca2+, good correlation (r-values 0.96–1.00) was observed for all comparative analyzers and the biases were within clinically acceptable limits. Potassium, sodium, glucose, lactate and hemoglobin measured with stat analyzers was highly correlated with measurements performed using the laboratory analyzers, r-values 0.89–1.00 and slopes 0.83–1.07. Mean differences with significant bias (p