How do you accurately determine the level of glucose in the blood?
The medical laboratory diagnosis of this chronic disease is based on blood sugar tests.
The principally used analytical methods are enzymatic assays, based on the hexokinase (an enzyme involved in the metabolic pathway of glycolysis) or on the glucose oxidase reaction. These methods are recommended and highly standardised with an inter-laboratory imprecision (CV) < 2.6% (1.4.5). (2)
In addition, an in vitro decrease in plasma glucose of 5-7% per hour has been reported on non-centrifuged samples immediately after collection. Cellular activity continues to affect glucose concentration.
The effect of the additive NaF - Sodium Fluoride (additive present in the glucose tubes, grey cap) on glycolysis appears only 2 to 3 hours after blood sampling.
Organisational constants are also taken into account.
According to the recommendations of the American Diabetes Association and the American Association of Clinical Chemists lithium heparin plasma samples should be stored on ice slurry and plasma should be separated within 30 minutes or tubes with citrate buffer should be used. (3)
These recommendations are complicated to implement, particularly for off-site pre-analytical sampling. Added to this are the constraints of transport and storage temperatures, which can be variable.
Having a sample tube with an anticoagulant that immediately preserves the glucose concentration is therefore essential for correct classifications.
Furthermore, it is interesting to have a sampling tube that blocks glycolysis at T0 thanks to an additive that inhibits the first enzyme (Hexokinase) necessary for the first biochemical reaction of glucose degradation: Citrate. (4)
That is why Greiner Bio-One has developed the VACUETTE® FC Mix tube for the inhibition of glycolysis for the precise determination of blood sugar content.
- Stabilisation immediately after collection for 48 hours
- Based on the in vivo value (almost 100%)
- Avoids false negative diagnoses of diabetes patients
- Stabilisation allows for longer transport and storage times
(2) Effectiveness of citrate buffer-fluoride mixture in Terumo tubes as an inhibitor of in vitro glycolysis
(3) Sacks DB, Arnold M, Bakris GL, et al. Guidelines and recommendations for laboratory analysis in the diagnosis and management of diabetes mellitus. Clin Chem 2011; 57: 793–798.
(4) Blood Glucose Determination: Effect of Tube Additives
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