Je li kvantitativno mjerenje nezrelih granulocita na hematološkomanalizatoru sysmex xn-1000 doista pouzdano?

Introduction: The diagnostic and prognostic significance of immature neutrophils has been extensively documented. To ensure rapid response to our clinicians we aimed to verify the reliability of the quantitative measurement of immature granulocytes (IG) on a Sysmex XN-1000 hematology analyzer (HA). Methods: The verification protocol included the precision study performed on both patient and commercial quality control (QC) samples (repeatability and total precision) and the comparison with the reference manual method (light microscopy) according to CLSI H20-A2:2007 guidelines. Two blood smears were prepared and stained using the May Grünwald Giemsa (MGG) technique. Two experienced medical laboratory scientists differentiated all duplicate stained slides. The method imprecision was expressed as a coefficient of variation in percentages (CV %) and compared to the manufacturer’s performance criteria (25.0 % or 0.12 x 109/L IG for repeatability; 30 % for total precision). An average bias between the automated method and the manual method was calculated using the Bland-Altman plot and compared to the manufacturer’s acceptance criteria (±1.5 % IG). According to the manufacturer, a correlation coefficient between methods should be >0.80. Additionally, a rank correlation between methods was performed. Statistical analysis was performed in MedCalc® v23.1.1 statistical software (MedCalc Software Ltd, Ostend, Belgium) Results: The repeatability on both patient and QC samples was within the acceptance criteria, ranging from 8.7 % for high IG concentrations to 18.3 % for low IG concentrations. Total imprecision for all concentration levels was within the acceptance criteria (<6 %). One hundred patients were included in the comparison study. IG values ranged from 0.7 to a maximum of 23.3 x 109/L. Bland-Altman plot revealed a satisfactory positive absolute bias of 1.2 % IG (95 % CI: 0.9 – 1.5, P<0.0001). Rank correlation revealed a satisfactory correlation coefficient of 0.90 (95 % CI: 0.86 – 0.93, P<0.0001). Conclusions: The hematology analyzer Sysmex XN-1000 meets all the manufacturer’s specifications regarding quantitative IG measurements. The method has been verified and is suitable for daily routine work within the six-part differential blood count, thus significantly improving turnaround time in severe cases where every second to diagnosis count.