title: New fluorescent method (PLT-F) on Sysmex XN2000 hematology analyzer achieved higher accuracy in low platelet counting.
abstract: OBJECTIVE
  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 × 10(3)/μL (50 × 10(9)/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 × 10(3)/μL (50 × 10(9)/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 × 10(3)/μL (20 × 10(9)/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 × 10(9)/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 × 10(9)/L. PLT-F could be helpful in making better decisions for platelet transfusions.
authors.affiliation: Dept of Clinical Chemistry, Hematology & Immunology, Medical Center Alkmaar, Wilhelminalaan 12, 1815 JD Alkmaar, The Netherlands; m.g.schoorl@mca.nl.
authors.forename: Margreet
authors.initials: M
authors.lastname: Schoorl
authors.forename: Marianne
authors.initials: M
authors.lastname: Schoorl
authors.forename: Jeanette
authors.initials: J
authors.lastname: Oomes
authors.forename: Johannes
authors.initials: J
authors.lastname: van Pelt
mesh_terms: D001792:Blood Platelets / Q000502:physiology; D005453:Fluorescence; D006403:Hematologic Tests / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D008856:Microscopy, Fluorescence; D010976:Platelet Count / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D013921:Thrombocytopenia / Q000175:diagnosis*
keywords: PLT-F; PLT-O; Platelet counting; Sysmex XN2000 hematology analyzer; Transfusion platelet threshold