Aim: The aim is to evaluate the compatibility of sodium, potassium, and glucose measurement procedures of point-of-care (POC) blood analyzer and biochemistry auto-analyzer.

Methods: Sodium, potassium, and glucose test results performed in our laboratory between 01-30 March 2021 were obtained retrospectively. Sodium, potassium and glucose tests were analyzed simultaneously (within half an hour) in the auto-analyzer, and the POC blood analyzer was included in this study. The compatibility between the POC blood analyzer and auto-analyzer results was evaluated by Passing-Bablok regression analysis and Bland-Altman plots.

Results: Passing-Bablok regression were y=-33.25+1.25x, y=0.35+1x, and y=-4,182+1.045x for sodium, potassium and glucose, respectively. There was no significant deviation from linearity for sodium, potassium, and glucose (p=0.50, p=0.68, and p=0.48 respectively). The mean absolute difference were -1 mmol/L (95% CI=-7 to 5), -0.42 mmol/L (95% CI=-1.38 to 0.54), and -3.5 mg/dL (95% CI=-35.4 to 28.3) for sodium, potassium and glucose, respectively.

Conclusion: Sodium, potassium, and glucose measurement method procedures measured in the POC blood analyzer and auto-analyzers are compatible. Random distribution of differences between values measured by both methods around zero (not showing a systematic distribution) showed a good fit between the methods. The calculated bias values do not exceed limits determined by Clinical Laboratory Improvement Amendment (CLIA). According to the data we have obtained, reporting that the results obtained with the POC blood analyzer are compatible with the test results of the automated analyzer and sharing these results with clinicians will contribute to the effective use of the test results obtained with the POC blood analyzer for patients.

Keywords: Abbott i-Stat1, measurement procedure comparison, point of care analyzer, Siemens Advia 1800