title: The evidence for clinically significant bias in plasma glucose between liquid and lyophilized citrate buffer additive.
abstract: OBJECTIVE
  Citrate buffer additive has been suggested to be of supreme performance in inhibiting glycolysis. However, there is little evidence in the literature regarding the comparability of glucose concentrations in liquid and lyophilized citrate buffer containing tubes. The aim of this study was to compare glucose concentrations in tubes containing liquid (Glucomedics) and lyophilized citrate buffer (Terumo VENOSAFE™ Glycemia) additive, measured immediately after centrifugation.
  
  
  METHODS
  Blood was collected from forty volunteers into both Glucomedics and Venosafe Glycemia tubes. Blood was centrifuged within 15min from venipuncture and glucose concentration was measured immediately after centrifugation, on the Abbott Architect analyzer. Differences between glucose concentrations in Glucomedics and Terumo tubes were tested using the paired t-test. Mean bias was calculated and compared to recommended quality specification for glucose (i.e. 2.2%).
  
  
  RESULTS
  Glucose concentration in Terumo tubes was 3.4% lower than in Glucomedics tubes (P<0.001). The mean bias was clinically significant.
  
  
  CONCLUSIONS
  There is a clinically significant difference between glucose concentrations in liquid and lyophilized citrate buffer additive tubes (Glucomedics vs. Terumo tubes) measured immediately after centrifugation. This difference may affect the patient outcome due to the misclassification of diabetes.
authors.affiliation: Department of Laboratory Diagnostics, General Hospital Pula, Pula, Croatia. Electronic address: gjuricic@gmail.com.
authors.forename: Gordana
authors.initials: G
authors.lastname: Juricic
authors.affiliation: University Department of Chemistry, University Hospital Centre "Sestre Milosrdnice", Zagreb, Croatia.
authors.forename: Andrea
authors.initials: A
authors.lastname: Saracevic
authors.affiliation: University Department of Chemistry, University Hospital Centre "Sestre Milosrdnice", Zagreb, Croatia.
authors.forename: Lara Milevoj
authors.initials: LM
authors.lastname: Kopcinovic
authors.affiliation: Department of Laboratory Diagnostics, Psychiatric Hospital "Sv. Ivan", Zagreb, Croatia.
authors.forename: Ana
authors.initials: A
authors.lastname: Bakliza
authors.affiliation: Department of Medical Laboratory Diagnostics, University Hospital "Sveti Duh", Zagreb, Croatia.
authors.forename: Ana-Maria
authors.initials: AM
authors.lastname: Simundic
mesh_terms: D001786:Blood Glucose / Q000032:analysis*; D002021:Buffers; D002951:Citrates / Q000737:chemistry*; D005612:Freeze Drying; D006801:Humans
chemical_list: D001786:Blood Glucose; D002021:Buffers; D002951:Citrates
keywords: Diabetes; Glucomedics; Glycolysis inhibitors; Preanalytical phase; Venosafe Glycemia