Evaluation of Cobas b 101 HbA1c Analyzer Performance for Point-of-Care Testing

ABSTRACT

BACKGROUND: The use of point-of-care (POC) devices for evaluating HbA1c is increasing; accordingly, comparisons between these devices and central laboratory methods are important. In the present study, we evaluated the analytical performance of the cobas b 101 analyzer for POC HbA1c testing. METHODS: The analytical quality of the cobas b 101 system was assessed based on repeatability, within-laboratory precision, linearity, and lot-to-lot reproducibility. Two specimen types, i.e., EDTA whole blood and capillary blood, were examined using the cobas b 101 system and the Variant II Turbo instrument. RESULTS: The coefficient of variation for within laboratory precision was 5.22% for a normal HbA1c level and 2.56% for a higher HbA1c level. The method showed good linearity, with a coefficient of correlation of 0.990. In a comparison of two different HbA1c disk lots, a strong correlation (r=0.986) and a mean %difference of −2.9% were observed. The cobas b 101 results using EDTA whole blood were strongly correlated with the Variant II Turbo results (r=0.958), with a mean %difference of 0.8%; the cobas b 101 results using capillary blood were strongly correlated with the Variant II Turbo results, using EDTA whole blood (r=0.976), with a mean %difference of 2.0%. A comparison between HbA1c levels in EDTA whole blood and capillary blood obtained using the cobas b 101 showed a strong correlation (r=0.985) and a mean %difference of 1.3%. CONCLUSIONS: The cobas b 101 analyzer is convenient for the measurement of HbA1c levels for diabetes management.