Rate of Glucose Utilization by Blood Cells in Serum and Plasma Specimens With or Without Using Preservative

Objective: This study aims to estimate and compare the time-course change in blood glucose levels by blood cells in serum, and plasma with or without preservatives, which may reflect the rate of glucose utilization by blood cells. Method: This laboratory-based cross-sectional study was carried out using a blood specimen of 28 participants among which 14 were diagnosed with diabetes and 14 were non-diabetic. Fasting blood specimen was collected in a plain tube, Ethylene Diamine Tetra Acetic Acid (EDTA) tube, and EDTA+ Sodium Fluoride (NaF) tube. The test was performed by hourly estimation of glucose for 24 hours. Time-course changes in glucose levels in serum and plasma with or without NaF preservative were statistically compared using ANOVA test. Result: Serum and EDTA plasma glucose levels decreased gradually after the 3rd hour to 24th hour in comparison to EDTA+NaF plasma (p<0.05).  The rate of glucose utilization by blood cells was significantly higher in clotted blood and anticoagulated blood (EDTA) specimens in comparison with anticoagulated blood (EDTA) containing preservative (NaF) ((p<0.05). In addition, decreased rate of glucose utilization was observed in hyperglycemic specimens compared to that of normoglycemic blood. Conclusion: Higher rate of glucose utilization by blood cells observed in serum and EDTA plasma represents a pre-analytical error in a long-standing specimen. The use of preservative NaF with EDTA significantly prevents cellular glucose utilization and stabilize plasma glucose level.  In contrast, this study also shows further insight into the reduced cellular metabolic rate of glucose utilization in diabetes mellitus.