title: Measurement procedure for glucose in serum using liquid chromatography isotope dilution--tandem mass spectrometry (LC-ID-MS/MS).
abstract: BACKGROUND
  We developed and validated a measurement procedure for glucose using liquid chromatography-isotope dilution tandem mass spectrometry. The proposed method is intended to be used for setting target values in EQAS samples and for certification of glucose reference materials, including those in biological matrices.
  
  
  METHODS
  Serum samples were spiked with internal standard 13C6 D-glucose. Protein precipitation was performed with ethanol. The samples were vortexed and centrifuged. An aliquot of the supernatant was evaporated to dryness, the residue dissolved in elution buffer and injected into the LC-MS/MS system. Measurements were performed in the positive ion mode monitoring the Cs+ adducts for glucose at m/z 313 --> 132.9 and m/z 319 --> 132.9 for the internal standard.
  
  
  RESULTS
  The coefficient of variation (CV) of the measurement procedure for lyophilized, liquid, and fresh serum samples was between 0.27 and 1.77%. The bias from certified target values for NIST reference materials was < or = 0.62%. A Deming regression comparison demonstrated a good correlation of results obtained with the proposed LC-ID-MS/MS method and target values obtained in the internationally accepted IFCC-RELA ring trial using JCTLM-recognized reference measurement procedures.
  
  
  CONCLUSIONS
  The proposed LC-ID-MS/MS measurement procedure with traceability to SI units shows excellent accuracy and precision and is suitable for use as reference measurement procedure for certification of target values in lyophilized and fresh serum samples.
authors.forename: M
authors.initials: M
authors.lastname: Kress
authors.forename: D
authors.initials: D
authors.lastname: Meissner
authors.forename: U
authors.initials: U
authors.lastname: Kramer
authors.forename: M
authors.initials: M
authors.lastname: Spannagl
authors.forename: P
authors.initials: P
authors.lastname: Kaiser
mesh_terms: D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000032:analysis*; D002138:Calibration; D002853:Chromatography, Liquid / Q000592:standards; D006801:Humans; D007201:Indicator Dilution Techniques / Q000592:standards; D011237:Predictive Value of Tests; D012015:Reference Standards; D012044:Regression Analysis; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry / Q000592:standards
chemical_list: D015415:Biomarkers; D001786:Blood Glucose