Complementarity between Bayesian Internal Quality Control results management and External Quality Assessment bivariate z-score analysis: application to a concrete case study.

It is important that a clinical laboratory has implemented appropriate procedures for quality control, which includes both internal quality control (IQC) and external quality assessment (EQA) with the common goal to detect systematic errors and random errors. It is the case for both the Hemohub® Bayesian tools for IQC results interpretation and the ECAT EQA optimised bivariate z-scores analysis. On a concrete case study, we demonstrate both the higher sensitivity and specificity of optimised bivariate z-scores analysis than the univariate approach. The Bayesian IQC results interpretation like the ECAT analysis confirmed the explicit conclusion i.e. an increase of the random error corresponding to the increase of the inter assay coefficient of variation (CV) at the date of EQA samples runs. Improvement of repaired dysfunction could be then daily observed on IQC results and then confirmed on EQA results thanks to the complementarity of the two approaches.