BackgroundBlood 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, pCO2, pO2, 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.MethodsA cross‐sectional study was conducted with a sample size of 100. Each sample was measured for pH, pCO2, pO2, 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.ResultsStrong 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.ConclusionThis comparison study of pH, pCO2, pO2, 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.

Background Confirmatory hepatitis B surface antigen (HBsAg) is an assay used to distinguish weakly reactive from false-positive HBsAg results. Objective To determine the signal to cutoff (S/CO) value of chemiluminescence microparticle immunoassay (CMIA) HBsAg assay that should trigger follow-up confirmatory HBsAg testing. Methods All specimens with an initial S/CO value of 0.90–100.00 were subjected to repeat HBsAg testing after high-speed centrifugation. The specimens with an initial S/CO value in that range remained in the same range and were then followed up with confirmatory HBsAg testing. Result In total, 132 specimens had an S/CO value between 0.90 and 100.00 after high-speed centrifugation, followed by confirmatory HBsAg retesting. The S/CO value of HBsAg specimens for which the results required verification with confirmatory HBsAg was 0.98 (100% sensitivity, 3.3% specificity) through 9.32 (47.1% sensitivity, 100% specificity). Conclusion The HBsAg S/CO values (as determined by the chemiluminescent microparticle immunoassay [CMIA] method) that should trigger confirmatory HBsAg testing are 0.98–9.32.