Biochemia Medica, Vol. 26 No. 3, 2016.
Original scientific paper
https://doi.org/10.11613/BM.2016.038
The influence of sample freezing at -80°C for 2-12 weeks on glycated haemoglobin (HbA1c) concentration assayed by HPLC method on Bio-Rad D-10© auto-analyzer.
Katarzyna Bergmann
; Department of Laboratory Medicine, Nicolaus Copernicus University Collegium Medicum, Bydgoszcz, Poland
Grazyna Sypniewska
; Department of Laboratory Medicine, Nicolaus Copernicus University Collegium Medicum, Bydgoszcz, Poland
Abstract
Introduction: The aim of the study was to evaluate the effect of a single freeze/thaw cycle on HbA1c concentrations measured by commercially available HPLC method.
Materials and methods: Study included 128 whole blood samples collected from diabetic patients (N = 60) and healthy volunteers (N = 68). HbA1c concentrations were measured in fresh blood samples. Then samples were frozen at - 80 °C for up to 12 weeks. HbA1c was assayed by ion-exchange HPLC method on Bio-Rad D-10® analyzer. Variables were compared using Wilcoxon and ANOVA Kruskal-Wallis tests. Bias between HbA1c measured in fresh and frozen samples was calculated. The comparability of HbA1c concentrations was assessed by Bland-Altman plot.
Results: Median (IQR) HbA1c concentration was 45.3 (36.6–61.2) mmol/mol for fresh and 45.3 (36.6–60.6) mmol/mol for frozen/thawed samples. No significant difference in HbA1c concentrations was found comparing fresh and frozen/thawed samples (P = 0.070) in the whole group, as well as in healthy and diabetic subjects. The median calculated bias between fresh and frozen/thawed samples was 0% in whole group and healthy subjects, and 1.19% in diabetic patients. No significant difference was found between the biases according to baseline HbA1c values (P = 0.150). The Bland-Altman plot analysis showed a positive bias of 0.4% (95% CI: - 2.8 - 3.7%), which indicates high compliance between HbA1c values and no relevant influence of sample freezing on clinical significance of HbA1c measurement.
Conclusions: Storage for up to 12 weeks at – 80 °C with a single freeze/thaw cycle does not affect HbA1c concentrations measured with HPLC method on Bio-Rad D-10® analyzer.
Keywords
glycated haemoglobin; diabetes; sample storage; high performance liquid chromatography; preanalytical phase
Hrčak ID:
167709
URI
Publication date:
15.10.2016.
Visits: 1.758 *