AUTOMATION Flashcards
Two Most commonly used hema-analyzer principles
Electrical Impedance and Optical Light Scatter
Basic components of hema analyzers
Hydraulics, pneumatics, and electrical systems
Component of hema analyzer that includes an aspirating unit, dispensers, diluters, mixing chambers, aperture baths or flow cells or both, and a hemoglobinometer
Hydraulics system
Component of hema analyzer that generates the vacuums and pressures required for operating the valves and moving the sample through the hydraulics system
Pneumatics system
Component of hema analyzer that controls operational sequences of the total system and includes electronic analyzers and computing circuitry for processing the data generated
Electrical system
Other term for Electrical Impedance
Low voltage Direct Current
In electrical impedance, number of electrical pulses correlates with?
Number of cells
In electrical impedance, height of amplitude of electrical pulses correlates with?
Size or volume
Cell size or cell volume is plotted on
X axis
Cell number is plotted on?
Y axis
are graphic representations of cell frequencies versus sizes
Histograms
In a homogeneous cell population, the curve assumes a
symmetrical bell-shaped or Gaussian distribution.
RBC DILUTION FACTOR IN AUTOMATED HEMA ANALYZER
1:50,000
WBC DILUTION FACTOR IN AUTOMATED HEMA ANALYZER
1:500
The principle of cell counting is based on the detection and measurement of changes in electrical resistance produced by cells as they traverse a small aperture.
Electrical impedance
What is the relationship of the number of electrical pulses to the number of cells counted in electrical impedance measurement?
Directly proportional
What is the relationship of the height of the electrical pulses to the cell size or volume in electrical impedance measurement?
Directly proportional
These are used to display the pulses that are generated by the cells in an electrical impedance measurement
Oscilloscope screens
Refers to the passage of more than one cell at a time through the orifice causes artificially large pulses, which results in falsely increased cell volumes and falsely decreased cell counts.
Coincident
The use of _______ avoids many of the potential problems inherent in a rigid aperture system in the electrical impedance based instrument
Hydrodynamic focusing
Prevents recirculation of cells back into the sensing zone, and anomalously shaped pulses are edited out electronically.
Back wash or Sweep flow mechanism
What do you KNOW about Radiofrequency?
- It is used in conjunction with the DC electronic impedance
- The Radio Frequency or High voltage Alternating current
resistance measures the cell interior density or complexity - Increase pulse height of RF is directly proportional to the cell interior density
What are the interior density of the cell? (3)
- N:C ratio
- Nuclear density
- Cytoplasmic granulation
In optical scatter, it uses laser or non-laser light source. What is an example of a non-laser light source?
Tungsten halogen lamp
The detection of light scattered rays and their conversion into electrical signals is accomplished by
Photodetectors
Examples of photodetectors
Photodiodes and Photomultiplier tubes
What are the independent processes in Optical Light Scatter? Differentiate each if possible.
- Diffraction - bending of light around corners using small angles
- Refraction - bending of light because of change in speed using intermediate angles
- Reflection
- Dispersion
- Interference
It is used to prevent non-scattered light from entering the detector and are used to collect the scattered light
Blocker Bars
What are the different angles of light scatter that aid in cellular analysis? Explain each.
- Zero degree forward - cell size
- 2-3 degree forward low - cell size or volume
- 5-15 degree forward high angle - refractive index of cellular components
- 10 degree light scatter - cell structures or complexity
- 90 degree light scatter- Lobularity
- Depolarized 90, orthogonal or side angle light scatter - reflection and refraction of internal components, granularity
Combination of forward low angle LS and forward high angle LS
Differential Scatter
is the last of the manual cell-counting procedures to be automated and has been a primary focus of hematology analyzer advancement in recent years
Reticulocyte count
A supravital fluorescent stain used in Sysmex R-3000/3500 reticulocyte analyzer
Auramine O