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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
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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
PLT_DC RBC_DC Impedance Counting • Platelet count is fine when histograms are well defined • But in case of abnormality, platelet count suffers from Rbc interference
RET(Plt-O) Optical PLT Count • In those instances - Fluorescent Optical Platelet count would be preferable for several reasons
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
Accurate Platelet Counting 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
Limitations of Optical Platelet Counts • WBC fragments are included in the Optical Platelet Count • Generates a “Plt Abn Scattergram” flag
PLT-I PLT-O PLT-I PLT-O PLT Switching Algorithm RBC fragments/ small Rbcs: WBC fragments / giant platelets:
No PLT-I, Low reliability PLT-I is reported Yes No PLT-O, Low reliability PLT-O is reported Yes PLT Vote out 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