Influência do tipo de tubo de coleta de sangue na determinação da glicose: possível interferência da glicólise “in vitro”

Abstract

Glucose determination is susceptible to a recurrent pre-analytical error, called “in vitro” glycolysis, which can generate falsely decreased results. Thus, it is necessary to collect blood in adequate tubes and adopt strategies that prevent this chemical phenomenon to ensure a reliable result. Objective: To evaluate the stability of glucose concentration in blood samples collected in tubes with clot activator only, with activator gel / clot separator and with sodium fluoride / EDTA over 10 hours after collection. Material and methods: Blood from 29 individuals, collected by venipuncture after a 12-hour fasting, were evaluated. Blood samples were collected under vacuum, in 3 different collection tubes, and later centrifuged for up to 1 hour to obtain serum/plasma. Then, glucose quantification was performed every 1h after collection, for a period of 10h. Results: There is a greater drop in the concentration of glucose in the tube collected with clot activator alone since the time 2h, reaching a decrease of 11.4% at the time of 10 h. Discussion: The increase in the coefficient of variation of blood glucose as a function of the after collection indicates that the tube containing only clot activator is not the most suitable for the determination of blood glucose after 1 hour obtaining the serum . Conclusions: The results suggest that the most suitable tube for sample collection in which blood glucose will be determined, when it is possible to centrifuge it within 1 h, is the one with activator gel / clot separator. If it is not possible to perform the centrifugation during this period, the best choice would be the tube with sodium fluoride / EDTA.