Analytical validation of 39 clinical chemistry tests and 17 immunoassays on the Alinity analytical system.

The aim of this study was to perform the analytical validation of Alinity c and i analyzers (Abbott Laboratories, Chicago, IL, USA) for 39 clinical chemistry tests and 17 immunoassays. Precision was evaluated at least at two concentration levels for 5 days in quintuplicate, following CLSI EP15-A3. Method comparison included parallel analysis of leftover routine samples on Alinity analyzers and the previously used Cobas c501 and e601 (Roche Diagnostics, Mannheim, Germany). Linearity was tested by preparing sequential sample dilutions with high analyte concentration, following the CLSI EP6 document. For clinical chemistry tests, within-run coefficients of variation (CV) were up to 6.0% (beta-2-microglobulin), while between-run CVs up to 5.4% (immunoglobulin M). Among immunoassays, the highest within-run CV was obtained for vitamin B12 (6.9%), while between-run for CA 19-9 (4.3%). Complete agreement with Roche analyzers was observed for 16 (41%) clinical chemistry assays and 6 (35%) immunoassays. Half of all evaluated assays did not meet the desirable biological variation criteria for bias, being especially exceeded for alpha1-antitrypsin, apolipoprotein A1, ceruloplasmin, complement C3 and C4, hemoglobin A1c, lipoprotein (a) and myoglobin, as well as some tumor markers (CA 125, CEA, fPSA, AFP, and ferritin), hormones (cortisol, DHEA-S, insulin) and vitamins (25-OHD). Linearity in the tested ranges was confirmed. Overall, this study revealed that precision criteria derived from manufacturer's claims were not satisfied for all assays while comparison study for some assays yielded differences that imply the need for additional assay evaluation prior to introduction into routine practice.

Applied capillary electrophoresis system affects screening for monoclonal gammopathy in serum: verification study of two eight-capillary systems.

Capillary electrophoresis is a method with a long history of developments which enables monitoring of several pathological processes and has an irreplaceable role in screening for presence of M-protein. The aim of this study was to assess analytical performance of Sebia and Helena systems, as well as their screening efficiency for M-protein by identifying characteristic electrophoretic pattern abnormalities. The controls were analyzed in triplicate over a five-day period. Comparability testing was performed on 46 (Capillarys3Octa) and 49 (V8Nexus) serum samples with routinely used Capillarys2. Electropherograms (EPGs) were reviewed by two specialists independently to select samples for further processing by immunofixation. All precision test results met the eligibility criteria by Ricos et al. The correlation coefficients higher than 0.8 indicated excellent comparability although the results were slightly more comparable among the same manufacturer systems. There were no variations in observed abnormalities in EPGs when Capillarys systems were compared, but a disparity was detected in 11/49 EPGs on comparing Capillarys2 and V8Nexus. The cause of the detected difference could be in a different graphical presentation of the findings and in a lesser resolution of the applied buffer. The impression is that the V8Nexus system combined with the utilized buffer provides greater resolution in the alpha-1 and alpha-2 globulin fractions, but that it declines in the gamma globulin fraction. The precision and estimated accuracy criteria were met by both systems. Comparison results implied that capillary systems are not equally effective in M-protein screening, highlighting the necessity to include system screening efficiency in analytical evaluation.