Automated Blood Cell Analysis Flashcards
The detection and measurement of changes in electrical resistance produced by cells as they traverse a small aperture
Electronic impedance
Display the pulses that are generated by cells as they interrupt the current
Oscilloscope
The number of pulses is proportional to…..
The number of cells counted
The height of the voltage pulse is proportional to….
The volume of the cell
Increases RBC/PLT counting sensitivity
Aperture diaphragm size
The passage of more than one cell at a time through the orifice causes artificially large pulses.
Causes falsely increased cell volumes and falsely decreased cell counts
Coincident passage
Causes erroneous pulses and falsely increased cell counts
Recirculation of cells back into the sensing zone
Provides laminar flow that allows the central sample stream to marrow sufficiently to separate and align the cells into single file passage through the sensing zone
Hydrodynamic focusing
Resistance to high voltage EM current flowing between both electrodes simultaneously.
Measures conductivity to correlate cell interior density
Radio frequency
A hydrodynamically focused sample stream is directed through a flow cell past a focused light source
Optical scatter
Light source of flow cytometry
Tungsten halogen lamp or helium neon laser
Light scatter results from absorption, diffraction, refraction to be detected and converted into electrical signals by photodetectors
Flow cytometry
Forward angle light scatter correlates with
Call volume due to diffraction of light
Side scatter correlates with
Degree of internal complexity due to refraction and reflection of light
RBC principle instrument
Impedance
