Performance evaluation of platelet counting of Abbott Alinity hq and Sysmex XN‐9000 automated hematology analyzer compared with international reference method

Abstract

Introduction Accurate platelet counting is essential for risk assessment of bleeding and thrombosis. Abbott Alinity hq hematology analyzer was recently introduced, and its performance in platelet counting has yet to be evaluated comprehensively. In this study, we evaluated the performance of the optical platelet counting of Abbott Alinity hq (Alinity‐PLT) and the impedance and fluorescent platelet counting of Sysmex XN‐9000 (XN‐PLT‐I and XN‐PLT‐F) compared with the international reference method. Methods Blood samples were analyzed via Alinity hq and XN‐9000 with PLT‐F channel. Immuno‐platelet (ImmnoPLT) reference method was performed with CD41/CD61 antibodies using FACSLyricTM flow cytometer (BD). Precision was determined using 10 replicates in a single run, and the platelet counts of Alinity‐PLT, XN‐PLT‐I, XN‐PLT‐F, and ImmnoPLT were compared. Results At a platelet count of 13 × 109/L, the CVs of Alinity‐PLT, XN‐PLT‐I, and XN‐PLT‐F were 4.2%, 6.7%, and 4.3%, respectively, and at a platelet count of 44 × 109/L, all showed a CV of less than 3%. For the total 210 samples, all three methods showed a very strong correlation with ImmunoPLT (r > 0.99). For platelet levels below 20 × 109/L, XN‐PLT‐F showed the strongest correlation with ImmunoPLT (r = 0.975), and for platelet levels of 20‐100 × 109/L, Alinity‐PLT and XN‐PLT‐I were comparable to ImmunoPLT. For platelet levels of 100‐450 × 109/L, XN‐PLT‐I was the most comparable to ImmunoPLT, and for platelet levels above 450 × 109/L, Alinity‐PLT was comparable to ImmunoPLT. Conclusions All three methods were highly correlated with ImmunoPLT, and each method had different performance advantages according to the platelet levels.

Alinity hq platelet results are equivalent with the international reference method in thrombocytopenic samples

“…Our results by Alinity hq have demonstrated tight within‐run imprecision, with an average %CV of 4.7% in samples with PLT concentration of <50 × 10 9 /L. This result is consistent with recently published Alinity hq results 28 and is equivalent, or better than those obtained with other contemporary hematology analyzers 17,19 . The 3.3%CV of the IRM can be explained by the higher number of events analyzed by flow cytometry, and the difference between the Alinity hq and IRM within‐run precision performance is not clinically significant.…”

“…Many studies have assessed concordance between various PLT methods, including the IRM 5,17,28 with correlation and regression statistics on various sample cohorts; analytical performance, however, must also be considered in order to fully understand the accuracy of single PLT measurements. Our results by Alinity hq have demonstrated tight within-run imprecision, with an average %CV of 4.7% in samples with PLT concentration of <50 × 10 9 /L.…”

Platelet Phagocytosis by Neutrophils, Platelets Lack of Granules and Giant Platelets Result in Pseudothrombocytopenia

“…At present, there are no reported cases of the simultaneous occurrence of these three abnormal forms. The optical platelet-counting method identi es platelets with laser light scatter technique shown as a reliable method for accurate platelet counting in thrombocytopenic patients, this technique combines scattered light and side uorescence detectors., a uorescent dye (oxazine) is used beforehand to stain platelets and reticulocytes [18][19][20].However, this technique also fails to detect engulfed platelets and platelets without granules In multiple tests, the number of platelets counted by manual was signi cantly higher than that counted by instrument (Table1). This also indicate that instrumentation is not a complete substitute for manual testing, and peripheral blood smears must be performed in cases of PTCP.…”

Pseudothrombocytopenia—A Review on Causes, Occurrence and Clinical Implications

“…A fluorescent dye (oxazine) is used beforehand to stain platelets and reticulocytes. It has been shown as a reliable method for accurate platelet counting in thrombocytopenic patients, and one of the most reliable for taking clinical decisions on platelet concentrate transfusions [ 112 , 113 , 114 , 115 , 116 , 117 ]. Compared to PLT-O, PLT-F can more clearly distinguish PLT from other blood cells, and is also more accurate for analysis of giant thrombocytes [ 4 , 115 ].…”

“…More importantly, it has recently been described as effective in correcting spurious low PC on the two platforms Sysmex XN 9000 and Mindray SF-cube, even suggesting that an alternative anticoagulant will probably no longer be necessary in case of EDTA-PTCP [ 14 , 108 ]. Limitations of this enumeration technique are longer turnaround time, increased reagent costs due fluorescent dye, and need of larger sample volume [ 113 ]. Additional studies with large number of patients are still needed to demonstrate that Sysmex XN 9000 and Mindray SF-cube are actually correcting spuriously low platelet counts.…”