Comparison of Arterial and Capillary Blood Glucose Measurement Accuracy Using a Glucometer in Diabetic Patients Undergoing Cardiac Surgery

Abstract

Background & Aims Effective blood glucose measurement is crucial for reducing complications in diabetic patients. This study aims to compare the accuracy of measuring the capillary and arterial blood glucose levels using a glucometer in diabetic patients undergoing cardiac surgery. Materials & Methods This cross-sectional study was conducted on 73 patients with diabetes undergoing heart surgery at a specialized cardiology hospital in the north of Iran. A demographic/clinical questionnaire was first completed. Three types of blood glucose samples were taken from the patients: An arterial line sample sent to the laboratory, an arterial line sample monitored by a glucometer, and a capillary sample monitored by a glucometer. The average error and average absolute error of blood glucose measurement methods were calculated to record the error rate. Statistical analyses were conducted using ANOVA, Bonferroni post hoc test, McNamar’s test, linear regression, and Bland-Altman plots to validate the accuracy of glucometer values against the lab results. Results Most of the participants were male (64.38%). Their mean age was 60.34±8.26 years. The mean absolute error between the laboratory glucose level and the arterial glucometer value was 11.12±13.16 mg/dL. The mean absolute error between the laboratory glucose level and the capillary glucometer value was 18.96±17.43 mg/dL, while the mean absolute error between the arterial and capillary glucometer values was 15.93±78.17 mg/dL. Statistical indicated a significant difference in the average absolute errors among the three methods (P<0.001), with capillary glucometer value demonstrating a greater error than arterial glucometer value. The arterial glucometer value achieved an accuracy rate of 94.5%, whereas the capillary glucometer value achieved 89% accuracy compared to the laboratory results. The two methods together exhibited an error rate of <20%. Conclusion While both capillary and arterial blood glucose measurements using a glucometer are viable for assessing blood glucose levels in diabetic patients undergoing cardiac surgery, the arterial approach is favored for blood glucose measurements.