Verification of analytical performance of sodium assay on the Abbott architect ci8200: Experience of the central laboratory Mohammed VI Oujda

Introduction: Sodium is the main extracellular cation. It plays a fundamental role in maintaining osmotic pressure and hydroelectrolyte balance, and is therefore implicated in many pathological conditions. Sodium determination is a basic biochemistry laboratory test.
Objective: the aim of our work is to verify the method of sodium determination by potentiometry on the Architect CI 8200 automated system (Abbott), in order to meet the quality requirements for laboratory accreditation under standard NF ISO 15189. Materials and methods: following the recommendations of NF EN ISO 15189, we evaluated the repeatability, intermediate precision, accuracy and uncertainty of measurement of the serum sodium assay on the Architect CI 8100 automated system, as well as a mirror comparison of the two Architect CI 8100 1 and 2. The CV values obtained were compared with those set by learned societies (SFBC and RICOS).
Results and discussion: The results obtained show satisfactory repeatability for the 3 low, medium and high levels, with CV1= 1.1%, CV2=0.8% and CV3= 0.76% respectively, and satisfactory intra-laboratory reproducibility for the 3 low, medium and high levels, with CV1= 1.05%, CV2= 0.95% and CV3= 0.75% respectively. For comparison, the Bland-Altman diagram showed that the mean bias between the two automata was of the order of 0.29%, the correlation coefficient r= 0.98 with a mean difference of 0.40 mmol/l, a standard deviation of 0.675 mmol/l and a linear regression equation Y = 1.027 X - 4.073. Corrective measures were envisaged to remedy the various errors identified. To solve any malfunction in a sustainable way, it is essential to search for the anomaly by applying the Ishikawa diagram.
Conclusion: The results obtained have enabled us to verify the performance of the sodium assay method and compare it with the analytical objectives set, in order to meet the regulatory and normative requirements to which our laboratory is committed.