Comparison of point‐of‐care and central laboratory analyzers for blood gas and lactate measurements

BACKGROUND: Blood gas analysis and blood lactate measurement have important roles in patient management. Point‐of‐care (POC) testing simplifies and provides rapid blood gas and lactate measurements. This study aimed to compare pH, pCO(2), pO(2), and lactate measurements between a POC device and a benchtop blood gas analyzer typically used in a hospital central laboratory, and to evaluate the inter‐device variability of the POC device. METHODS: A cross‐sectional study was conducted with a sample size of 100. Each sample was measured for pH, pCO(2), pO(2), and lactate using a Nova pHOx plus L(®) benchtop blood gas analyzer in the central laboratory and an i‐STAT(®) handheld POC device. The results of both devices were compared using Pearson or Spearman correlation coefficients and Bland‐Altman tests. Testing of the inter‐device variability was done by using three different i‐STAT(®) devices, and the results were compared statistically. RESULTS: Strong correlations were observed for all test results. In Bland‐Altman analysis, ≥95% of the results were within the limits of agreement, with the exception of lactate, which had only 93%. The results that were beyond the limits were primarily lactate levels >8 mmol/L. Biases between the benchtop analyzer and the i‐STAT(®) were not clinically significant, except pH. No significant inter‐device variability was observed between the i‐STAT(®) analyzers. CONCLUSION: This comparison study of pH, pCO(2), pO(2), and lactate measurements between Nova pHOx plus L(®) and i‐STAT(®) analyzers showed good agreement. However, lactate measurement results >8 mmol/L on the i‐STAT(®) analyzer should be interpreted with caution.