Evaluation of an assay for serum 1,5-anhydroglucitol (GlycoMark™) and determination of reference intervals on the Hitachi 917 analyzer

1,5-Anhydroglucitol (1,5-AG) is a glucose analogue, which is decreased in hyperglycemic individuals. We report the technical performance of an assay (GlycoMark™) on a chemistry analyzer, evaluation of analyte stability and determination of reference intervals for 1,5-AG in a non-diabetic US population. NCCLS protocols were followed to evaluate the reagent on a Hitachi 917 chemistry analyzer. Intra- and interassay imprecision ranged from 1.3% to 3.8% and 0.79% to 3.7%, respectively. The assay was linear to 110 μg/ml. Interference from triglyceride, hemoglobin and bilirubin was <10% to concentrations of 12.6 mmol/l, 12.1 and 911.4 μmol/l, respectively. Correlation coefficients between lot numbers on the Hitachi 917 and between analyses on the Hitachi 917 and the Hitachi 7170 analyzers were >0.99. The lowest limit of detection was 0.49 μg/ml (mean±2 S.D.). 1,5-AG was stable at 4°C for 7 days, at 22°C for 5 days, at -80°C for 14 days and for three freeze-thaw cycles at -80°C. The US reference intervals (nonparametric 2.5th-97.5th percentiles) were 10.2-33.8 μg/ml (males) and 5.9-31.8 μg/ml (females). The performance of the GlycoMark™ assay for the measurement of 1,5-AG was acceptable on the Hitachi 917 analyzer.