Evaluating the Quality Performance of Sysmex and Mindray Hematology Analyzers for Blood Cell Counting Based on External Quality Assessment Data.

backgroundThis study aims to evaluate the analytical performance of Sysmex and Mindray hematology analyzers for white blood cell (WBC), red blood cell (RBC), and platelet (PLT) counting. We calculated Z-scores and total allowable error (TEa) based on External Quality Assessment (EQA) data to provide references for laboratory quality improvement.

methodsSysmex and Mindray blood cell analysis systems are categorized into six groups based on instrument models, detection methods, or reagent properties: Sysmex (1), Sysmex (2), Sysmex (3) and Mindray (1), Mindray (2), Mindray (3). EQA data for WBC, RBC, and PLT from the National Center for Clinical Laboratories (NCCL) EQA programs (2020-2024) were collected. Robust means and standard deviations were calculated to determine Z-scores for each Sysmex and Mindray instrument group, assessing bias relative to assigned values. TEa for each instrument group of laboratories participating in the EQA activity (TEa-Lab) was calculated using bias and the robust coefficient of variation (CV). Subsequently, TEa-Lab was compared with the minimum, desirable, and optimal tiers of biological variation -based TEa (TEa-BV) to evaluate the performance specifications of participating laboratories.

resultsThere were 10 instances where the absolute Z-score |Z| for WBC was greater than 2. These were distributed among the groups as follows: Sysmex (1): 0, Sysmex (2): 1, Sysmex (3): 0, Mindray (1): 3, Mindray (2): 3, Mindray (3): 3. For RBC, 22 instances had |Z| greater than 2, distributed as follows: Sysmex (1): 2, Sysmex (2): 3, Sysmex (3): 4, Mindray (1): 6, Mindray (2): 4, Mindray (3): 3. For PLT, 3 instances had |Z| greater than 2, with counts of Sysmex (2): 1, Sysmex (3): 1, Mindray (1): 1. Regarding the comparison TEa, for WBC, all groups, except Mindray (2), which met the desirable standard, achieved the optimal standard. For RBC, the Sysmex (3) group achieved the optimal standard; the Mindray (2) group met only the minimum standard, while the other groups met the desirable standard. For PLT, only the Sysmex (3) and Mindray (3) groups reached the minimum standard. The other peer groups did not meet the minimum standard.

conclusionsZ-scores and TEa-Lab calculated from EQA data provide reliable insights into the performance of hematology analyzers. The performance of Sysmex and Mindray analyzers is stable and demonstrates advanced capabilities. This effectively supports the maintenance of laboratory quality systems and serves as a reference for mutual recognition of test results between laboratories.