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New Fluorescent Method (PLT-F) on Sysmex XN2000 Hematology Analyzer Achieved Higher Accuracy in Low Platelet Counting

Margreet Schoorl, Marianne Schoorl, Jeanette Oomes, Johannes van Pelt PhD
DOI: http://dx.doi.org/10.1309/AJCPUAGGB4URL5XO 495-499 First published online: 1 October 2013


Objectives: In thrombocytopenia, high accuracy and precision of low platelet count is essential for appropriate decisions. The recently introduced Sysmex XN2000 analyzer (Sysmex, Kobe, Japan) offers 3 methods for platelet counting: impedance (PLT-I), optical (PLT-O), and a new fluorescence method (PLT-F). The precision of the PLT-F method in blood samples with platelet counts less than 50 ×103/μL (50 × 109/L) was investigated and compared with the ICSH CD61-ImmunoPLT reference method. For comparison, PLT-I and PLT-O were determined on the Sysmex XN2000 and Sysmex XE2100 analyzer.

Methods: Blood samples with platelet counts less than 50 ×103/μL (50 × 109/L) (n = 37) were analyzed on the Sysmex XN2000 and XE2100 analyzers. The CD61-ImmunoPLT method was performed on a Beckman Coulter FC-500 flow cytometer (Miami, FL).

Results: At a platelet count of 20 ×103/μL (20 × 109/L), reproducibility for PLT-I, PLT-O, and PLT-F on the XN2000 demonstrated coefficients of variation of 9.3%, 8.5%, and 3.0%, respectively. Correlation between PLT-O on the XN2000 and XE2100 yielded an r value of more than 0.977. Linear regression analysis between the PLT-F and CD61-ImmunoPLT methods resulted in a PLT-F of 0.71*CD61 – 0.8 (r = 0.988). Linear regression between PLT-F and PLT-O on the XN2000 resulted in a PLT-F of 1.05*PLT-O – 2 (r = 0.975), and using the transfusion threshold of 20 × 109/L platelets resulted in a PLT-F of 0.90*PLT-O – 0.4 (r = 0.956).

Conclusions: The new PLT-F method demonstrated excellent results for reproducibility in samples with platelet counts less than 50 × 109/L. PLT-F could be helpful in making better decisions for platelet transfusions.

Key Words:
  • Platelet counting
  • PLT-O
  • PLT-F
  • Sysmex XN2000 hematology analyzer
  • Transfusion platelet threshold
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