Comparison of arterial and capillary blood glucose measured using a glucometer and blood gas analyzer, and its association with acuity of illness: A longitudinal cohort study

Objectives: Dysglycemia is one of the major complications in the critical care unit. Many factors interfere with the accuracy of blood glucose measurements among critically ill patients; therefore, results must be interpreted with caution. This longitudinal cohort study assessed the level of agreement between blood glucose values obtained from capillary and arterial blood using a glucometer over time and its association with the Acute Physiology and Chronic Health Evaluation-II score. Materials and Methods: Eighty-one participants were selected by convenience sampling method. Arterial and capillary blood blood glucose levels were measured at three points of time (i.e. on intensive care unit admission, at 24 hours, and 36 hours after cardiac surgery) using a Control-D glucometer and blood gas analyzer. Statistical analysis: Inferential analyses like two-way repeated measures analysis of variance, Wilcoxon’s signed rank test, intraclass correlation coefficient, and receiver operating characteristics analysis were used. Results: The study results revealed that there was a good agreement between the arterial and capillary blood sugar measured using a glucometer (intraclass correlation coefficient ranges from 0.95 to 0.98). The difference between the blood glucose levels measured using different methods was comparable (P > 0.05) during the admission at the range of hyperglycemia. However, at 24 and 36 h after cardiac surgery, the capillary blood significantly (P < 0.05) overestimated blood glucose level (by18–22 mg/dL and 30 mg/dL) as compared to arterial blood glucose measured using a glucometer and blood gas analyzer. Conclusions: Arterial blood in a glucometer can be used for measuring blood glucose levels in a critical care setting whenever an arterial access is available, or when a blood gas analyzer is not accessible.