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
Historically, which calibration has been considered the preferred method for calibration of multichannel hematology analyzers
Whole blood calibration
Whole blood calibration has been completely replaced by the use of _______ assayed using reference methods
Commercial calibrators
_________ are associated with higher risk of CVD disease and may have use in assessing a patient’s risk of thrombosis
High MPV values
Parameters that are directly obtained from histogram
WBC count, RBC count, Hemoglobin
Parameters that are derived from RBC Histogram
MCV and RDW
Parameters that are derived from platelet Histogram
MPV and PDW / MPV and platelet ct.
Parameters that are computed
Hematocrit, MCH, MCHC
What cells are involved in 3 part differential count?
Lymphocytes, Monocytes and Granulocytes
What cells are involved in 5 part differential count?
Neutrophils,Lymphocytes, Monocytes,Eosinophils, & Basophils
What cells are involved in 6 part differential count?
neutrophils, lymphocytes, monocytes, eosinophils, basophils, and immature granulocytes
What is Ohm’s Law?
Current x Resistance
Particles with a cell size of 36 and 360fl are counted as
RBC
If the particles’ cell size is 2 - 20fl, it is counted as
Platelets
TRUE / FALSE
If the RBC’s are larger than normal, the curve will shift toward the right 5.
If the RBC’s are smaller than normal the curve will shift to the left
True
Enumerate the positive instrumental errors.
Bubbles, Extraneous electrical pulses and Aperture plugs
Enumerate the negative instrumental errors
Excessive lysing of RBCs
Improper setting of aperture current or threshold.
Positive or Negative instrumental error?
Either
Erythrocytes with a normal RDW are heterogeneous in character and exhibit very little anisocytosis on a peripheral blood smear
Erythrocytes with an increased RDW are referred to as homogeneous and exhibit a high degree of anisocytosis on a peripheral blood smear
A. Both true
B. Both false
C. 1st false, second true
D. 1st true, second false
Both false
Homogenous
Heterogenous
It is the measure of the average volume of platelets in a sample
MPV
What kind of anticoagulated tube causes a platelet to change in shape?
EDTA
What is the relationship of MPV to Platelet count?
Inversely proportional
Increase MPV or Decrease MPV
- Idiopathic thrombocytopenic purpura
- After splenectomy
- DIC
- WAS
- Aplastic anemia
- After chemotherapy
- Sickle cell anemia
- Heterozygous thalassemia
- Megaloblastic anemia
- Myeloproliferative disorders
- Increase MPV
- Increase MPV
- Increase
- Decrease
- Decrease
- Decrease
- Increase
- Increase
- Decrease
- Increase
The _______ is a measure of the uniformity of platelet size in a blood specimen
PDW
This parameter serves as a validity check and monitors false results. A normal PDW is less than 60%.
A. Both true
B. Both false
C. 1st true, 2nd false
D.1st false, 2nd true
C. 1st true, 2nd false
It is originally designed to measure physical properties of cells based on their ability to deflect light
Flow cytometry
TRUE or FALSE
The main advantage of flow cytometry is its ability to rapidly and simultaneously analyze multiple parameters in a small number of cells.
FALSE
Large Numbers
Specimens most commonly used in flow cytometry for diagnosing hematological malignancies
BM, PBS, Lymphoid tissue
Peripheral blood and bone marrow specimens for flow cytometric analaysis should be processed within ______ from the time of collection
A. 24 hours
B. 1-2 days
C. 36 hours
D. 2-4 days
B. 1 - 2 days
Preferred anticoagulant in BM and peripheral blood specimens awaiting for flow cytometric analysis
Heparin
Specimens must be transported to a flow cytometry laboratory at what temperature?
A. Cold temp
B. Hot temp
C. Room temp
D. Body temp
TRUE OR FALSE
Bone marrow biopsy specimens and solid tissue specimens, including core biopsy samples, are submitted in culture media to maintain vitality or on saline-moistened gauze
False
Viability
A fluorescent dye used in flow cytometry to stain specimen and test its viability
propidium iodide or 7-aminoactinomycin
Known as Simultaneous analysis of multiple markers. It is a technique routinely used for a diagnosis and follow-up of hematologic disorders
Multicolor
or
multiparameter flow cytometry
The detector situated directly in line with the illuminating laser beam measures forward scatter (FS or FSC), which is proportional to particle weight and height.
A photodetector located to the side measures side scatter (SS or SSC), which reflects surface complexity and internal structures such as granules and vacuoles
A. Both true
B. Both false
C. 1st true, 2nd false
D. 1st false, 2nd true
D. 1st false, 2nd true
Volume or size
In laser flow cytometers, light scatter is used to measure the intrinsic size and granularity of the cell.
In addition, fluorescence can be used to measure extrinsic features by adding reagents
A. Both true
B. Both false
C. 1st true, 2nd false
D. 1st false, 2nd true
A. Both true
Enumerate the parts of flow cytometer
Fluidics, light source (laser), a detection system and a computer
the most common light source used in flow cytometers because of the properties of stability, and monochromatism
Laser light (Argon light)
Enumerate the fluorescent dyes or fluorochrome used
acridine orange, thioflavin T, pyronin Y, phycoerythrin (PE), and fluorescein isothiocyanate
When dual color analysis is desired, what dyes are used?
FITC AND phycoerythrin
Fluorochromes are covalently bonded to monoclonal antibody molecules.
The fluorochrome, excited by the laser light, will fluoresce at a shorter wavelength
A. Both true
B. Both false
C. 1st true, 2nd false
D. 1st false, 2nd true
C. 1st true, 2nd false
Longer
________is the heart of the flow cytometers instrument; it controls all decisions regarding data collection, analysis, and cell sorting.
Computer
Cell populations with similar physical properties such as size, cytoplasmic complexity, and expression of a specific antigen form _______ on data generated by flow cytometers
Clusters
It is an electronic boundary an operator uses to delineate cell clusters.
Gate
First immunophenotypic marker of megakaryocyte differentiation or lineage
CD41 and CD61
What dye is used in flow cytometry to detect malarial parasites?
Acridine orange
TRUE / FALSE
Radio frequency (RF) or alternating current (AC) resistance is a modification sometimes used in conjunction with DC electronic impedance.
True
Scatter properties at different angles may be plotted against each other to generate two-dimensional ____________ or _________
Cytograms or Scatterplots
Increase pulse height of RF is _________ to the cell interior density
Directly propotional