Abstract Background Sigma metrics is a useful way to assess the quality of analytical performance for clinical chemistry assays. Mindray BS-2800M is a recently launched high-end clinical chemistry autoanalyzer. In 2024, we launched 10 new assays with concentrated reagents and two modified assays with improved reagents for enhanced performance on the BS-2800M analyzer. This study evaluated the analytical performance of these assays with sigma metrics. Methods The total error model with precision and bias for sigma metrics is used. The precision study was run according to EP05A3 for 20 testing days, two runs per day and 2 replicates per run, with two commercial controls and three serum sample pools with concentrations at or near the medical decision level(s) or near the limits of the reference intervals for each assay. The biases were estimated by comparing the mean of the measured results by the testing method for all samples at all levels independently vs. their corresponding target values set by the reference methods. The total allowable error (TAE) limits are adapted from those defined by CLIA2024. Bilirubin Direct(DBILn) and Cystatin C(CysC) were not on the TAE list from CLIA. We used those from European Federation of Laboratory Medicine (EFLM) biological database goals. Sigma metrics values were calculated for each assay as (TAE -|Bias%|) / CV%. Conventional sigma metrics categorizations were used for the assessment: world class (6 sigma); excellent (5-6 sigma); good (4-5 sigma); marginal (3-4 sigma); poor (3 sigma). Results Assay’s sigma metrics values were found slightly varied with analyte concentrations and types of testing materials. Six assays with concentrated reagents, Total Bilirubin(TBILn), DBILn, Uric Acid(UAn), Carbon Dioxide(CO2n), Aspartate transaminase(ASTn), Glucose(GLUn) and two modified assays Creatinine(Crea-S) and CysC demonstrated superior performances being in world class category (6 sigma) with all concentrations and all materials tested. Three assays, with the concentrated reagents, Albumin(ALBn), Alanine transaminase(ALTn) and Total protein(TPn), showed very good performance being in excellent category (5-6 sigma) and UREAn showed very good performance being in good category (4-5 sigma) at low concentrations while, at high concentration, showed being in world class category (6 sigma). On average sigma metrics from each concentration for every assay, all assays shown superior performances. Conclusion From this evaluation, we concluded that recently launched Mindray ten assays with concentrated reagents and two modified assays can meet the high standard for good performances. Six of ten assays assessed demonstrated superior performance in 6 sigma metrics category. Three assays, ALBn, ALTn and TPn in this assessment showed excellent sigma metrics, 5-6. One assay, UREAn in this assessment showed 4-5 sigma metrics. Overall, these assays demonstrated very good performance and they are suitable for use in routine clinical laboratories.
Dai et al. (Wed,) studied this question.