A-106 Sigma Metric Performance of Chemistries on the Abbott Alinity c Analyzer

Abstract

Abstract Background The analytical performance of the Abbott Alinity c (Abbott Park, IL) was compared to our current Abbott Architect analyzers using sigma metrics. Methods Sigma metrics of 28 chemistry analytes on our six Abbott Alinity analyzers was compared to three Abbott Architect 16 000 analyzers and one Architect 8000 analyzer using Bio-Rad Multiqual quality control (QC) (Hercules, CA). Method imprecision was estimated for each assay using the cumulative coefficient of variation (CV) of 12 months data for each analyzer at three QC concentrations and calculating the average sigma. Method bias was estimated by comparing each analyzer QC mean to peer group QC means. Sigma values were calculated for each method as (TEa—Bias%)/CV% using allowable total error (TEa) from three sources: the CLIA proficiency testing evaluation limits, Australasian Association of Clinical Biochemistry allowable limits of performance (RCPA quality assurance programs Pty limited, Adelaide, Australia) and desirable biological variation (Ricos C et al, Scand J Clin Lab Invest. 1999, 59(7):491–500). Average sigma values were generated for each analyte and graded as optimal >6 sigma; good 5–6 sigma; marginal 3–5 sigma; or poor <3 sigma. Results Assay sigmas varied across QC concentrations and between analyzers of the same platform. Na, Cl, and CO2 had the lowest sigma performance. Since the sigma calculations are dependent on TEa, tighter TEa limits (Ricos and RCPA) generated lower sigmas compared to the wider CLIA TEa limits especially for Ca, Cl, total bilirubin, CO2, Na, total protein, and HDL. Conclusion None of the chemistries met optimal six sigma performance for all analytes, concentrations of QC and sources of TEa. However, the assay performance between analyzer platforms was comparable.