S GRIEBENOW<sup>1

1</sup>Greiner Bio-One, Kremsmünster, Austria

Background: The aim of the study was to show the comparison of glucose concentration in specimens spun directly after blood collection to specimens stored in whole blood at room temperatures as well as the long term stability of initial glucose concentration in specimens spun directly after blood collection. The recommended additive for stabilizing the glucose concentration is citrate, EDTA and sodium fluoride in order to prevent glycolysis. The study was designed to evaluate tubes containing that additive indicating a superior performance to sodium fluoride/EDTA.
Method: Fifteen healthy volunteers were recruited and venous blood drawn into 4 blood collection tubes (VENOSAFE™ FC, Terumo; VACUETTE® FX NaF/EDTA and two samples VACUETTE® FC Mix, Greiner Bio-One) of which three different glucose tubes to be centrifuged directly after blood collection and the second sample of FC Mix to be centrifuged after 48h storage in whole blood. All samples were inverted according to the manufacturers’ recommendations. Directly after blood collection, the plasma was measured immediately after centrifugation in order to obtain initial values of 30 min for comparison evaluations of all other time points by using the Hexokinase method on a Beckman Coulter AU640. The glucose concentration was determined after 24h, 48h, 72h and 96h in order to show the long-term stability.
Results: The stability of glucose concentration up to a 96h time period has been shown. Even the specimens which were centrifuged 48h after blood collection and kept for further stability testing at room temperature, demonstrated a stable glucose concentration up to 96h. The glycolysis results in a 7.7% lower initial glucose concentration in currently commercial tubes containing just sodium fluoride and EDTA. The deviations of single glucose concentration determinations were found to be within analytical tolerances.
Conclusion: The VACUETTE® FC Mix tube is a blood collection tube suitable for reliable determination of blood glucose. It is found to be useful in improving the stability of glucose concentration up to 96h primarily in case of long transport distances without having to use a secondary tube.