Implementation of new Westgard rules suggested by the Westgard Advisor software for five immunological parameters.

INTRODUCTION

Knowledge and systematic evaluation of analytical errors is the task of internal analytical quality control management. The aim of this study was to assess whether the Westgard rules proposed by Bio-Rad's Westgard Advisor software are more efficient in the monitoring of analytical performance than those previously in use.

MATERIALS AND METHODS

The study was carried out on the nephelometer Atellica NEPH630 (Siemens Healthineers, Erlangen, Germany). Five parameters were chosen: serum immunoglobulin A (IgA), alpha 1 - antitrypsin (AAT), prealbumin, lipoprotein (a) (Lp(a)) and ceruloplasmin. The study was divided into 4 phases (A, B, C, D): phase A - old rules used (1, R and 2); phase B - first introduction of new rules (30 days), (1/2 for IgA; 1/2/R/4/10 for the remaining parameters); Phase C - second intervention (after 60 days) 1/2/R/4 for IgA and Lp(a), 1/2/R/4/8 for prealbumin and ceruloplasmin and 1/2/R/4/10 for AAT; and Phase D - values at the end of the study (1 for IgA, 1/2/3/R/3/12 for AAT and ceruloplasmin, 1/2/R/4/8 for prealbumin and 1/2/R/4/10 for Lp(a).

RESULTS

At the end of the study the coefficient of variation (CV%), bias (%) and sigma for IgA were 2.55%, - 1.09% and 5.33, respectively; for AAT 3.88, - 2.21 and 3.25; for prealbumin 3.99, - 0.14 and 2.95; for Lp(a) 8.02, - 0.34 and 3.81; for ceruloplasmin 2.48, - 3.65 and 3.49.

CONCLUSIONS

By using newly suggested rejection rules, we did not observe an improvement in monitoring of analytical performance.