Precision of glucose measurements in control sera by isotope dilution/mass spectrometry: proposed definitive method compared with a reference method.
This improved isotope-dilution gas chromatographic/mass spectrometric (GC/MS) method, in which [13C]glucose is the internal standard, meets the requirements of a Definitive Method. In a first study with five reconstituted lyophilized sera, a nested analysis of variance of GC/MS values indicated considerable among-vial variation. The CV for 32 measurements per serum ranged from 0.5 to 0.9%. However, concentration and uncertainty values (mmol/L per gram of serum) assigned to one serum by the NBS Definitive Method (7.56 +/- 0.28) were practically identical to those obtained with the proposed method (7.57 +/- 0.20). In the second study, we used twice more [13C]glucose diluent to assay four serum pools and two lyophilized sera. The CV ranged from 0.26 to 0.5% for the serum pools and from 0.28 to 0.59% for the lyophilized sera. In comparison, results by the hexokinase/glucose-6-phosphate dehydrogenase reference method agreed within acceptable limits with those by the Definitive Method but tended to be slightly higher (up to 3%) for lyophilized serum samples or slightly lower (up to 2.5%) for serum pools.
Pelletier
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O
Arratoon
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C
D001774:Blood Chemical Analysis / Q000379:methods; D001786:Blood Glucose / Q000032:analysis / Q000592:standards*; D004796:Clinical Enzyme Tests / Q000379:methods; D005612:Freeze Drying; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D011865:Radioisotope Dilution Technique; D013223:Statistics as Topic
D001786:Blood Glucose