Assessment of Intra- and Intercapillary Variability in HbA1c Measurement Using the Sebia Capillarys OCTA3 Analyzer

Hemoglobin A1c (HbA1c) measurement is crucial for diabetes monitoring. Validation of analytical methods ensures the reliability of results. We verified the analytical performance of HbA1c measurement in each capillary of the Capillarys OCTA3 automated capillary analyzer, following the French accreditation committee guide. For each capillary and each HbA1c level, we evaluated repeatability, intermediate precision, accuracy, robustness, and measurement uncertainty. Results were compared to acceptance limits from French Society of Clinical Biology (SFBC), European Federation of Clinical Chemistry and Laboratory Medicine (EFLM), Réseau d'identification et de Communication en Oncologie et Sénologie (RICOS), and Clinical Laboratory Improvement Amendments (CLIA). A comparison with the high-performance liquid chromatography (HPLC) method was performed on 37 samples using linear regression and Bland-Altman analysis. Repeatability coefficient of variations (CVs) were less than 1.1% for both levels, consistent with supplier and SFBC (3.8%) thresholds. Precision CVs were 1.24% (normal) and 1.3% (pathological), below SFBC and supplier limits but above the strict EFLM standard. Accuracy showed consistent biases between 0% and 1.02%. Method comparison showed acceptable agreement. Expanded uncertainties were 3.10% (normal) and 2.89% (pathological), exceeding EFLM recommendations (1.8%). Westgard and CLIA sigma indices confirmed satisfactory robustness; EFLM indices were lower for some capillaries, limiting Six Sigma use. The OCTA3 analyzer demonstrated excellent analytical performance. Individual capillary verification yielded satisfactory results. Despite uncertainty exceeding EFLM recommendations and variable robustness, this method is reliable for routine clinical use.