engleski

Preliminary evaluation of eight less frequent endocrine assays designed for MAGLUMI 800 chemiluminescence immunoanalyzer

Transition to new analytical systems and methods requires end-user verification to ensure acceptability for routine use. Our aim was to verify precision of MAGLUMI 800 immunoassay analyzer for 17-hydroxyprogesterone (17-OHP), 25- hydroxy vitamin D (25(OH)D), aldosterone, androstenedione, growth hormone (GH), insulin- like growth factor 1 (IGF-1), insulin-like growth factor-binding protein 3 (IGFBP-3) and renin, as well as to assess their comparability with the routinely used assays. Precision was evaluated at two levels following the CLSI EP15-A2 protocol. Method comparison included parallel analysis of 40 routine samples for each assay on MAGLUMI 800 and the routinely used automated or manual immunoassays. Within-run coefficients of variation (CV) ranged from 0.8% (androstenedione) to 14.5% (aldosterone), between-run CVs from 1.0% (IGFBP-3) to 12.8% (renin), while within- laboratory (total) precision CVs were from 2.1% (IGFBP-3) to 14.9% (renin). All assays with the exception of IGF-1 and 25(OH)D at the low concentration control level, satisfied biological variation criteria for imprecision. Passing-Bablok regression showed proportional difference for 17-OHP and aldosterone, constant for androstenedione, while both constant and proportional difference was revealed for 25(OH)D, GH and IGF-1. Statistically significant relative biases higher than the desirable biological variation acceptance criteria were observed for 17-OHP, 25(OH)D, aldosterone, androstenedione and IGF-1. The evaluated assays need further assessment as well as verification of reference intervals in order to be suitable for introduction into routine practice in our laboratory. Our study clearly demonstrates that we are still far from achieving immunoassay standardization and comparability of results.

Immunoassay ; hormones ; validation study ; reproducibility of results ; standardization

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