Glucose variation in centrifuged serum and lithium-heparin gel tubes stored for up to 96 hours at room temperature or 4 °C.
Author(s): Balboni F, Burbui S, Lippi G
Publication: Scand J Clin Lab Invest, 2018, Vol. 78, Page 546-550
PubMed ID: 30755098 PubMed Review Paper? No
Purpose of Paper
This paper investigated the stability of glucose during storage of lithium heparin plasma and serum at room temperature and 4˚C. The effects on residual blood counts were also investigated.
Conclusion of Paper
Glucose levels were significantly lower than baseline in serum stored at room temperature or 4˚C for 24 h or lithium heparin plasma stored at either temperature for 3 h. While the decline in serum glucose did not exceed the specified performance specification of 6.4% even after 96 h, the decline in lithium heparin plasma glucose levels exceeded 6.4% between 6 and 24 h at both temperatures. Regardless of tube type, the mean decrease per hour was significantly higher in specimens stored at room temperature than those stored at 4˚C. The mean decrease per hour in lithium heparin plasma was not associated with white blood cell, red blood cell, or platelet counts.
Studies
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Study Purpose
The purpose of this study was to compare the stability of glucose during storage of lithium heparin plasma and serum at room temperature and 4˚C. The effects on residual blood counts were also investigated. Blood was collected from 60 out-patients into Vacuette lithium heparin tubes with gel separator, K2EDTA tubes, and serum gel separator tubes. Specimens in lithium heparin and serum tubes were immediately placed on ice and transported to the laboratory. Specimens were centrifuged at 1800 x g for 30 min within 30 min of collection. Thirty lithium heparin plasma and 30 serum specimens were then stored capped at room temperature while the remaining 30 of each type were stored capped at 4˚C. Glucose levels were measured 0, 3, 6. 24, 48, 72, and 96 h after centrifugation using the reference hexokinase assay on a Beckman Coulter AU480. A threshold error of less than 6.4% was set as the performance specification based on a prior publication. Whole blood counts were determined in K2EDTA blood and in serum and lithium heparin plasma immediately after centrifugation.
Summary of Findings:
Serum had no countable red blood cells, white blood cells, or platelets but lithium heparin plasma retained some white blood cells and platelets (approximately 10% and 5% of those in EDTA blood, respectively), regardless of storage temperature. Glucose levels were stable in serum stored at room temperature or 4˚C for up to 6 h, but significant declines were noted at both temperatures after 24 h (P<0.001); however, none of these declines exceeded the specified performance specification of 6.4%. The mean decrease per hour was significantly higher in specimens stored at room temperature than those stored at 4˚C (0.03 versus 0.01, P<0.001). Significant declines in glucose levels were noted in lithium heparin plasma stored for 3 h or more at either temperature (P<0.001) and the decline exceeded 6.4% between 6 and 24 h for both temperatures. The mean decrease per hour was greater in specimens stored at room temperature than 4˚C (0.67 versus 0.21, P<0.001). The mean decrease per hour in lithium heparin plasma was not associated with white blood cell, red blood cell, or platelet counts.
Biospecimens
Preservative Types
- None (Fresh)
Diagnoses:
- Not specified
Platform:
Analyte Technology Platform Cell count/volume Hematology/ auto analyzer Carbohydrate Clinical chemistry/auto analyzer Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Biospecimen Acquisition Anticoagulant Potassium EDTA
Lithium heparin
None
Storage Storage temperature Room temperature
4˚C
Storage Storage duration 30 min
3 h
6 h
24 h
48 h
72 h
96 h
Biospecimen Acquisition Type of collection container/solution Lithium heparin with gel separator tube
K2EDTA tube
Serum gel separator