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It takes acid, rather than ice, to freeze glucose.

van den Berg SA, Thelen MH, Salden LP, van Thiel SW, Boonen KJ - Sci Rep (2015)

Bottom Line: We describe the effect of a variety of commonly used blood collection tubes on in vitro stability of glucose.Sodium fluoride alone does not reduce in vitro glycolysis in the first 120 minutes after phlebotomy.NaF-EDTA-citrate based test tubes provide the best pre-analytical condition available.

View Article: PubMed Central - PubMed

Affiliation: Dept. of Clinical Chemistry and Hematology, Amphia Hospital, Breda, The Netherlands.

ABSTRACT
Plasma glucose levels provide the cornerstone of diabetes evaluation. Unfortunately, glucose levels drop in vitro due to glycolysis. Guidelines provide suitable conditions which minimize glycolysis, such as immediate centrifugation or the use of ice/water slurry storage containers. For obvious practical reasons, most laboratories use blood collection tubes containing glycolysis inhibitors. We describe the effect of a variety of commonly used blood collection tubes on in vitro stability of glucose. Furthermore, we looked at the validity of the assumption that glycolytic activity is minimal when blood is kept in an ice/water slurry. Sodium fluoride alone does not reduce in vitro glycolysis in the first 120 minutes after phlebotomy. Addition of citrate almost completely prevented in vitro glycolysis, but showed a positive bias (0.2 mmol/l) compared to control. This is partly due to a small drop in glucose level in control blood, drawn according to the current guidelines. This drop occurs within 15 minutes, in which glycolysis has been described to be minimal and acceptable. NaF-EDTA-citrate based test tubes provide the best pre-analytical condition available. Furthermore, glucose levels are not stable in heparinized blood placed in an ice/water slurry. We strongly advise the use of NaF-EDTA-citrate based test tubes in diabetes research.

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Related in: MedlinePlus

Time and temperature dependent changes of glucose concentration.(A): Time dependent change in core temperature and (B): changes in glucose concentration in heparinized blood placed in an ice/water slurry. Lines represent mean plus SD.
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f2: Time and temperature dependent changes of glucose concentration.(A): Time dependent change in core temperature and (B): changes in glucose concentration in heparinized blood placed in an ice/water slurry. Lines represent mean plus SD.

Mentions: Given the stability of the glucose concentration in the NaF-EDTA-citrate test tubes, we hypothesized that glucose concentration might have dropped in the control tubes, even though the tubes were stored only shortly and in an ice/water slurry. A possible reason could be the time needed to cool the blood in the test tube, due to the composition of the test tube wall and the blood volume. We measured core tube temperature in 3 test tubes and found that, in ice water, core temperature dropped to approximately 5° within 3 minutes (Figure 2a). We collected heparinized blood in 7 volunteers, which was immediately placed in an ice slurry after phlebotomy. Glucose concentration dropped in 5 of the cases and although the average drop was limited, it ranged from −0.07 mmol/l to −0.29 mmol/l (Figure 2b).


It takes acid, rather than ice, to freeze glucose.

van den Berg SA, Thelen MH, Salden LP, van Thiel SW, Boonen KJ - Sci Rep (2015)

Time and temperature dependent changes of glucose concentration.(A): Time dependent change in core temperature and (B): changes in glucose concentration in heparinized blood placed in an ice/water slurry. Lines represent mean plus SD.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4352852&req=5

f2: Time and temperature dependent changes of glucose concentration.(A): Time dependent change in core temperature and (B): changes in glucose concentration in heparinized blood placed in an ice/water slurry. Lines represent mean plus SD.
Mentions: Given the stability of the glucose concentration in the NaF-EDTA-citrate test tubes, we hypothesized that glucose concentration might have dropped in the control tubes, even though the tubes were stored only shortly and in an ice/water slurry. A possible reason could be the time needed to cool the blood in the test tube, due to the composition of the test tube wall and the blood volume. We measured core tube temperature in 3 test tubes and found that, in ice water, core temperature dropped to approximately 5° within 3 minutes (Figure 2a). We collected heparinized blood in 7 volunteers, which was immediately placed in an ice slurry after phlebotomy. Glucose concentration dropped in 5 of the cases and although the average drop was limited, it ranged from −0.07 mmol/l to −0.29 mmol/l (Figure 2b).

Bottom Line: We describe the effect of a variety of commonly used blood collection tubes on in vitro stability of glucose.Sodium fluoride alone does not reduce in vitro glycolysis in the first 120 minutes after phlebotomy.NaF-EDTA-citrate based test tubes provide the best pre-analytical condition available.

View Article: PubMed Central - PubMed

Affiliation: Dept. of Clinical Chemistry and Hematology, Amphia Hospital, Breda, The Netherlands.

ABSTRACT
Plasma glucose levels provide the cornerstone of diabetes evaluation. Unfortunately, glucose levels drop in vitro due to glycolysis. Guidelines provide suitable conditions which minimize glycolysis, such as immediate centrifugation or the use of ice/water slurry storage containers. For obvious practical reasons, most laboratories use blood collection tubes containing glycolysis inhibitors. We describe the effect of a variety of commonly used blood collection tubes on in vitro stability of glucose. Furthermore, we looked at the validity of the assumption that glycolytic activity is minimal when blood is kept in an ice/water slurry. Sodium fluoride alone does not reduce in vitro glycolysis in the first 120 minutes after phlebotomy. Addition of citrate almost completely prevented in vitro glycolysis, but showed a positive bias (0.2 mmol/l) compared to control. This is partly due to a small drop in glucose level in control blood, drawn according to the current guidelines. This drop occurs within 15 minutes, in which glycolysis has been described to be minimal and acceptable. NaF-EDTA-citrate based test tubes provide the best pre-analytical condition available. Furthermore, glucose levels are not stable in heparinized blood placed in an ice/water slurry. We strongly advise the use of NaF-EDTA-citrate based test tubes in diabetes research.

Show MeSH
Related in: MedlinePlus