B-034 Evaluation of the Analytical Performance of Sebia CAPI 3 HbA1c Assay

Abstract

Abstract Background HbA1c has been the most important marker for glycemic control and for the diagnosis of diabetes mellitus. The NGSP has invested significant efforts in the standardization of the HbA1c assays, and several analytical methods have been developed. We evaluated the analytical performance of the Sebia CAPI 3 HbA1c assay, which is determined by capillary electrophoresis. Additionally, samples with and without hemoglobin variants are analyzed, and results are compared to two HPLC-based methods. Methods Control materials are used in the precision study, which are included in the Sebia CAPI 3 HbA1c kit (Lisses, France). Linearity study is assessed with the linearity materials from LGC Maine Standards (Cumberland Foreside, ME). Carryover is determined by the EP Evaluator (Colchester, VT) with total 21 aliquots of a high and a low HbA1c sample assayed in a specific order. Accuracy study is determined by whole blood patient samples without hemoglobin variants (n = 40) and with hemoglobin variants (n = 8, mostly with Hb S of 30–40%). Results from Sebia CAPI 3 are compared to the current laboratory method (BioRad Variant II Turbo) (Hercules, CA) and the TOSOH G8 (Tokyo, Japan). Both are HPLC-based methods. Results The within-run precision at a mean of 5.5% HbA1c has a CV at 1% (n = 24), and the between-run precision at the level of 5.5% and 8.7% HbA1c has a CV at 1% (n = 20) and 2% (n = 20), respectively. Linearity study demonstrates the analytical measuring range is between 3.1% and 20.8%, although each laboratory might establish its own clinical reportable range. Carryover is passed based on the automatically calculated error limit in EP Evaluator (3 times the SD of the Low-Low results). The accuracy study shows the Sebia results correlate well with percent bias at 2% for BioRad Variant II Turbo and 3% for TOSOH G8 in samples with (n = 8) and without (n = 40) hemoglobin variants. Conclusion The Sebia CAPI 3 HbA1c assay is based on capillary electrophoresis principle, which is a recognized method by NGSP. The assay has demonstrated good precision, a wide analytical measuring range and minimum carryover. The results are comparable to two HPLC-based methods and are well within the total allowable error of 6% by NGSP in samples with and without hemoglobin variant.