title: Sedimentation by gravity stabilizes plasma glucose for up to 60 minutes.
abstract: OBJECTIVE
  Glucose levels decrease in whole blood in vitro, but there are several methods that minimize the loss, including special tubes and ice. This study evaluated whether sedimentation by gravity in an upright position was a viable alternative.
  
  
  METHODS
  Lithium heparinized blood was collected from 20 individuals without a diagnosis of diabetes. The samples were allowed to sediment at ambient temperature and were tested in quadruplicate at 30 minute intervals. A Repeated Measures ANOVA compared the means of each time-point.
  
  
  RESULTS
  Plasma glucose results were not statistically different between 30 minutes and 60 minutes after collection (p = 0.156). At 90 minutes after collection, glucose was significantly different than the initial glucose readings (p <0.001). Each reading thereafter also showed a statistically significant difference from the initial reading.
  
  
  CONCLUSIONS
  Samples for glucose measurement are stable in lithium heparin for no longer than 60 minutes when held in an upright position prior to centrifugation.
authors: Clinical Laboratory Sciences Program, University of West Florida, Pensacola, FL 32514, USA. kbehan@uwf.edu
authors: Kristina Jackson
authors: KJ
authors: Behan
authors: Marcia
authors: M
authors: Dumas
authors: Michael
authors: M
authors: Johnston
mesh_terms: D000925:Anticoagulants / Q000737:chemistry; D001774:Blood Chemical Analysis / Q000379:methods*; D001786:Blood Glucose / Q000737:chemistry*; D001800:Blood Specimen Collection / Q000379:methods*; D006112:Gravitation; D006493:Heparin / Q000737:chemistry; D006801:Humans
chemical_list: D000925:Anticoagulants; D001786:Blood Glucose; D006493:Heparin