title: Increased plasma glucose levels after change of recommendation from NaF to citrate blood collection tubes.
abstract: OBJECTIVE
  To evaluate changes in plasma glucose measurements in an unselected patient population after a change of recommendation from NaF to citrate blood collection vacuum tubes.
  
  
  METHODS
  Glucose (n=460 751) and HbA1c (n=55 190) determinations during a period of approximately three years before and after the tube change were extracted from a laboratory information system.
  
  
  RESULTS
  Median values for plasma glucose determinations increased from 6.03 before to 6.28mmol/L after the tube change. The proportion of glucose determinations above the WHO limit for impaired fasting glucose (6.1mmol/L) and the medical decision limit for diabetes (7.0mmol/L) increased from 48.1 to 55.4% after the change.
  
  
  CONCLUSIONS
  The change from NaF to citrate tubes caused higher glucose values, and consequently more glucose determinations above the decision limit for diabetes.
authors.affiliation: Department of Medical Sciences, Clinical Chemistry, Uppsala University, Uppsala, Sweden. Electronic address: peter.ridefelt@medsci.uu.se.
authors.forename: Peter
authors.initials: P
authors.lastname: Ridefelt
authors.affiliation: Department of Medical Sciences, Clinical Chemistry, Uppsala University, Uppsala, Sweden.
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Åkerfeldt
authors.affiliation: Department of Medical Sciences, Clinical Chemistry, Uppsala University, Uppsala, Sweden.
authors.forename: Johanna
authors.initials: J
authors.lastname: Helmersson-Karlqvist
mesh_terms: D001786:Blood Glucose / Q000187:drug effects*; D001800:Blood Specimen Collection / Q000009:adverse effects*; D002951:Citrates / Q000009:adverse effects* / Q000737:chemistry; D006801:Humans; D012969:Sodium Fluoride / Q000009:adverse effects* / Q000737:chemistry
chemical_list: D001786:Blood Glucose; D002951:Citrates; D012969:Sodium Fluoride
keywords: Blood collection tube; Glucose; Plasma; Preanalytical process; Sample stability