Optimization of imprecision and cost saving on hemoglobin A1c controls through aliquot freezing

Marrón, Pablo Isidro; Soria, Pilar Rosel; Ramos, Pedro Alía; Moreno, Miguel-Ángel Navarro

doi:10.1515/cclm.2008.236

Cited by 2 publications

(1 citation statement)

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“…Marron et al compared imprecision of Lyphocheck ® Diabetes Control Bilevel (Bio-Rad Laboratories, CA, USA) measured on HPLC instrument ( 12 ). Control material was stored up to 7 days in 2–8 °C and alternatively frozen in 10 µL aliquots at –80 °C.…”

Section: Discussionmentioning

confidence: 99%

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

Bergmann

Sypniewska

2016

Biochem Med

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IntroductionThe 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 methodsStudy 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.ResultsMedian (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.ConclusionsStorage 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.

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Section: Discussionmentioning

confidence: 99%