title: Technical and clinical validation of the Greiner FC-Mix glycaemia tube.
abstract: BACKGROUND
  Measurement of adequate glucose concentrations is complicated by in vitro breakdown of glucose due to glycolysis. Unlike the commonly used NaF-EDTA and NaF-oxalate phlebotomy tubes, citrated NaF-EDTA tubes are reported to directly and thereby completely inhibit glycolysis. Recently, Greiner introduced the Vacuette® FC-Mix NaF-EDTA-citrate tube, currently the only NaF-citrate tube without volume-disturbing liquid additions available on the European market. Here we present its potential as alternative for the laborious and therefore unfeasible conditions for glucose sampling as recommended by the World Health Organization (WHO).
  
  
  METHODS
  The FC-Mix tube was tested against the WHO recommended method of optimal laboratory conditions, both in healthy volunteers and pregnant woman undergoing oral glucose tolerance test (oGTT) for screening of gestational diabetes mellitus (GDM). Glucose concentrations were measured after different incubation times (0-48 h) and temperatures (room temperature, 37 °C), both in uncentrifuged whole blood and centrifuged material.
  
  
  RESULTS
  Deming regression analysis shows that glucose concentrations measured in the FC-Mix tube correlate to the WHO recommended method. Stability is maintained at room temperature for 48 h and at least 24 h at 37 °C. The use of the FC-Mix tube was also validated in screening for GDM and proved comparable to the WHO recommended method in diagnostic outcome.
  
  
  CONCLUSIONS
  The new Greiner FC-Mix tube combines the easy handling of a routine tube with dry additive with the ability to immediately inhibit glycolysis as in the WHO method for optimal pre-analytical and analytical conditions and performs equally to those conditions when screening for GDM.
authors.affiliation: .
authors.forename: Eline A E
authors.initials: EAE
authors.lastname: van der Hagen
authors.affiliation: .
authors.forename: Marion J
authors.initials: MJ
authors.lastname: Fokkert
authors.affiliation: .
authors.forename: Amanda M D
authors.initials: AMD
authors.lastname: Kleefman
authors.affiliation: .
authors.forename: Marc H M
authors.initials: MHM
authors.lastname: Thelen
authors.affiliation: .
authors.forename: Sjoerd A A
authors.initials: SAA
authors.lastname: van den Berg
authors.affiliation: .
authors.forename: Robbert J
authors.initials: RJ
authors.lastname: Slingerland
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D002951:Citrates / Q000737:chemistry; D016640:Diabetes, Gestational / Q000175:diagnosis; D004492:Edetic Acid / Q000737:chemistry; D005260:Female; D005951:Glucose Tolerance Test; D006019:Glycolysis; D006461:Hemolysis; D006801:Humans; D018962:Phlebotomy / Q000295:instrumentation* / Q000379:methods / Q000592:standards; D011247:Pregnancy; D012969:Sodium Fluoride / Q000737:chemistry; D013696:Temperature
chemical_list: D001786:Blood Glucose; D002951:Citrates; D012969:Sodium Fluoride; D004492:Edetic Acid
keywords: NaF-EDTA-citrate; citrate; glycolysis; phlebotomy; pre-analysis