Preanalytical Variables Influence the Accuracy of Glucose Testing for Diagnostic Purposes

Abstract

Background: The accuracy of test outcomes is essential for the quality of patient care. To demonstrate the effect of processing delays on glucose levels, we evaluate the stability and decline of glucose in whole blood samples obtained in EDTA vacutainers, which are stored at varying temperatures, as well as the rate of glucose degradation in different color-coded vacutainers.
Methods: Whole blood collected via venipuncture into the vacutainer was carefully mixed to ensure homogeneity. In the temperature study, glucose concentrations were measured at the outset and subsequently at 30-minute intervals in samples preserved at different temperatures. For the study involving color-coded vacutainers, glucose levels in the specimens were assessed initially and at various intervals.
Results: In general, the concentration of glucose in stored whole blood decreased over time. The decline was most significant in the specimen kept at 37 °C when compared to those stored at 24 °C and at ice (0 °C). In the color-coded analysis, all vacutainers, with the exception of the gray top, exhibited a statistically significant decrease in glucose levels. The gray top vacutainer retained as much as 94.7±2.0% of its original glucose concentration even after a duration of 24 hours.
Conclusion: The gray top vacutainer preserves glucose levels to ensure diagnostic precision in situations where a delay in specimen processing is anticipated.