ABSTRACT
Background: The new XR-Series haematology analyser from Sysmex provides increased throughput and automation, along with a new reagent in WDF channel for optimised WBC differential. Methods: An analytical performance study for the XR analyser was conducted to evaluate the WDF channel parameters in comparison to the instrument specifications. Additionally, 7460 samples were measured on XR and XN analysers to compare selected parameters and flags, and 930 randomly selected samples were further evaluated with microscopy. Results: All investigated aspects of the analytical performance study for the XR fell within the manufacturer specifications. The correlation coefficients between the two systems for the parameters tested were greater than 0.983 for the main CBC and DIFF parameters, greater than 0.909 for the Extended Inflammation Parameters, and greater than 0.932 for the parameters used in the workflow rulesets of the Extended IPU. Similarly high sensitivities for the detection of abnormal cells were observed for the 'Blasts/Abn Lympho?' flag (XN: 100%, XR: 99.0%) and WPC abnormal flags ('Blasts?' or 'Abn Lympho?') (XN: 97.0%, XR: 96.0%). XN with WPC channel had a 26% reduction of false positive smears compared to XR with 22% reduction, a statistically non-significant difference. Conclusion: The XR analyser had very good analytical performance, and highly comparable results to the predecessor XN analyser in all investigated parameters, flags and workflow aspects.
ABSTRACT
BACKGROUND: Decisions on prophylactic platelet (PLT) transfusions are generally based on the recipient's PLT count, but few clinicians are aware of precision and accuracy of the PLT counting methods used by the clinical laboratory. Each PLT counting technology has its specific inaccuracy, especially in thrombocytopenic samples and therefore may impact decisions on PLT transfusions. STUDY DESIGN AND METHODS: Five routine PLT counting methods available in two hematology analyzers (Sysmex XN-2000 and Abbott CELL-DYN Sapphire) were investigated (impedance and optical on both analyzers and fluorescent on XN-2000), using the CD61 immunologic PLT method as a reference. The impact of counting inaccuracy on imaginary transfusion decisions was examined at various common PLT thresholds. RESULTS: In total 341 samples were analyzed, 178 of which had PLT counts of less than 35 × 109 /L. Despite excellent overall correlation with the reference method (r > 0.99), thrombocytopenic samples showed only modest correlation for impedance and XN-2000 optical methods. Sapphire optical and XN-2000 fluorescent methods correlated very well with the reference, albeit with bias in the very low range. We noticed potential risk of undertransfusion (ranging from 2% to 90%), depending on the threshold used. The risk of overtransfusion was small (<10%). CONCLUSIONS: The XN-2000 fluorescent PLT counting method showed excellent correlation with the CD61 reference count, closely followed by the CELL-DYN Sapphire optical method. XN-2000 impedance and optical and Sapphire impedance methods are not accurate enough for basing transfusion decisions on. Only XN-2000 fluorescent, Sapphire optical, and CD61 methods are sufficiently accurate for making appropriate clinical decisions in patients with severe thrombocytopenia.
