Sysmex XE-2100 Counting of Red Cells and Platelets by impedance & fluorescent techniques

Methods employed Red cells are measured by impedence only Platelets are measured in two channels – Impedance Channel (default) – Fluorescent Channel Impedance Channel is default count In instances of abnormality when the algorithm will come into play

Impedance Channel - Overview Red cells and platelets Hydrodynamic Focusing of cells to be counted DC aperture Impedance Excellent Linearity – with limitations

Impedance Counting Platelet count is fine when histograms are well defined But in case of abnormality, platelet count suffers from Rbc interference PLT_DC RBC_DC

Optical PLT Count In those instances - Fluorescent Optical Platelet count would be preferable for several reasons RET(Plt-O)

Optical System Higher sensitivity due staining of cells Better Rbc/plt resolution Necessary in – Small (Microcytic) RBC – Giant Platelets – Rbc Fragments

Measurements used in Optical System Forward Scatter - size of cells Side Scatter - internal structure (i.e size of nucleus) Fluorescence - Measurement of RNA/DNA stained Fluorescent Optical Platelet count is performed with reticulocyte count

In the presence of Rbc fragments, microcytic RBC or giant platelets, the PLT distribution curve is clearly affected However in the RET scattergram, the RBC and PLT-O clusters are obviously distinct Accurate Platelet Counting

Limitations of Optical Platelet Counts WBC fragments are included in the Optical Platelet Count Generates a “Plt Abn Scattergram” flag

 PLT-IPLT-O WBC fragments / giant platelets: PLT-IPLT-O  RBC fragments/ small Rbcs: PLT Switching Algorithm

PLT-I, Low reliability PLT-O, Low reliability PLT Vote out PLT-I is reported PLT-O is reported No Yes PLT Switching Algorithm

PLT Abn Distribution flag or Fragments? flag is detected from RBC channel or PLT-I/PLT-O count differences +/- 15% Changing the count?

The PLT-I/O Switching Rule For low-PLT# – PLT-O# may more reliable than PLT-I#, when PLT-I# are low Customizable switching trigger for PLT-I# – Default setting is 50.0x10^3/uL

Adding PLT-I/O switching rule