Introduction: Glycolysis continues after blood collection and may reduce glucose concentrations in vitro, potentially compromising diagnostic accuracy. The effectiveness of glycolysisinhibiting additives differs among blood collection tubes. Citrate rapidly inhibits glycolysis through immediate acidification, whereas fluoride acts more slowly by inhibiting enolase at a later stage of the glycolytic pathway. This study aimed to compare short-term glucose stability in four commonly used blood collection tubes under routine laboratory conditions. Methodology: Venous blood samples were collected from 100 volunteers into Rapid Serum Tubes (RST), Barricor tubes, Fluoride tubes, and Citrate tubes. Glucose concentrations were measured at 30 and 60 minutes after collection using the hexokinase method. A repeated-measures ANOVA was performed to evaluate the effects of Time, Tube Type, and the Time × Tube interaction (α = 0.05), followed by Bonferroni-adjusted pairwise comparisons. Results: At 30 minutes, glucose concentrations were highest in the Fluoride tube (5.528 mmol/L), followed closely by the Citrate tube (5.505 mmol/L), while lower values were observed in RST (5.434 mmol/L) and Barricor tubes (5.430 mmol/L). By 60 minutes, glucose levels had declined in all tubes; however, the decrease was more pronounced in serum-based tubes. RST values fell to 5.277 mmol/L and Barricor to 5.300 mmol/L, whereas Fluoride and Citrate tubes remained relatively stable at 5.449 mmol/L and 5.489 mmol/L, respectively. Overall, glucose decreased significantly between 30 and 60 minutes (mean decrease = 0.096 mmol/L, p <0.001; partial η² = 0.705). Tube Type also had a significant effect on glucose concentrations (F(3,297) = 42.06, p <0.001; partial η² = 0.298). Conclusion Fluoride and Citrate tubes provided the most effective preservation of glucose concentrations over 60 minutes, showing minimal glycolytic decline. In contrast, RST and Barricor tubes demonstrated significantly greater glucose loss, highlighting the importance of rapid processing when serum-based tubes are used.
Glucose