S GRIEBENOW¹, MJ FOKKERT², S ABBES², RJ SLINGERLAND<sup>2

1</sup>Greiner Bio-One, Kremsmünster, Austria, ²Department of Clinical Chemistry, Isala, Zwolle, The Netherlands

Background: Reliable detection of Gestational Diabetes Mellitus (GDM)is required to prevent maternal and fetal complications. The aim of the study was to show long term stability of initial glucose concentration in specimens spun directly after collection and compared to whole blood specimens stored at room temperatures. Recent guidelines from the German Diabetes Association recommend use of citrate, EDTA and sodium fluoride, as in VACUETTE® FC Mix tubes, to stabilize glucose levels.
Method: The study was conducted at ISALA Hospital (Netherlands) using VENOSAFE FC Mixture® versus VACUETTE® FC Mix tubes. Altogether, 43 pregnant donors who were healthy (n=19) and who were diagnosed with gestational diabetes by 75g-Oral Glucose Tolerance Test (n=24) were recruited. Venous blood was drawn from each donor into four tubes (two tubes each tube type). One tube of each type was spun directly after blood collection and the second one after whole blood storage for 48h at room temperature. Following collection, plasma was measured immediately after centrifugation to obtain initial values (fasting) and after 48h for evaluation of glucose stability using the Hexokinase method on a COBAS 8000.
Results: Evaluation of clinical results for glucose concentration was done on basis of maximal allowed deviation for a single value (for glucose 11%) according to the guidelines of the German Association of Quality Assurance. The utilization of both tubes for performance testing did not reveal any clinically significant deviations (p<0.05). The values of both tubes resulted in an initial highest deviation of 5.5%, and 6.4% after 48h (both healthy). Comparable highest deviations for initial values in relation to 48h values were obtained for both tubes with 5.4% (healthy) and 6.6% (GDM), respectively. The storage of whole blood specimens for 48h showed no significant deviation (10.5%, healthy).
Conclusion: Based on these results, the FC Mix blood collection tube is suitable for reliable determination of blood glucose diagnosing GDM. The stability of glucose concentration in whole blood specimens drawn in the VACUETTE® FC Mix tube and stored up to a 48h at room temperature has been shown.