AUTOMATION Flashcards by Andrea Eyao

Two Most commonly used hema-analyzer principles

Electrical Impedance and Optical Light Scatter

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Basic components of hema analyzers

Hydraulics, pneumatics, and electrical systems

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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

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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

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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

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Other term for Electrical Impedance

Low voltage Direct Current

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In electrical impedance, number of electrical pulses correlates with?

Number of cells

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In electrical impedance, height of amplitude of electrical pulses correlates with?

Size or volume

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Cell size or cell volume is plotted on

X axis

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Cell number is plotted on?

Y axis

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are graphic representations of cell frequencies versus sizes

Histograms

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In a homogeneous cell population, the curve assumes a

symmetrical bell-shaped or Gaussian distribution.

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RBC DILUTION FACTOR IN AUTOMATED HEMA ANALYZER

1:50,000

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WBC DILUTION FACTOR IN AUTOMATED HEMA ANALYZER

1:500

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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

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What is the relationship of the number of electrical pulses to the number of cells counted in electrical impedance measurement?

Directly proportional

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What is the relationship of the height of the electrical pulses to the cell size or volume in electrical impedance measurement?

Directly proportional

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These are used to display the pulses that are generated by the cells in an electrical impedance measurement

Oscilloscope screens

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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

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The use of _______ avoids many of the potential problems inherent in a rigid aperture system in the electrical impedance based instrument

Hydrodynamic focusing

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Prevents recirculation of cells back into the sensing zone, and anomalously shaped pulses are edited out electronically.

Back wash or Sweep flow mechanism

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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

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What are the interior density of the cell? (3)

N:C ratio
Nuclear density
Cytoplasmic granulation

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In optical scatter, it uses laser or non-laser light source. What is an example of a non-laser light source?

Tungsten halogen lamp

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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.

1. Diffraction - bending of light around corners using small angles 2. Refraction - bending of light because of change in speed using intermediate angles 3. Reflection 4. Dispersion 5. 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.

1. Zero degree forward - cell size 2. 2-3 degree forward low - cell size or volume 3. 5-15 degree forward high angle - refractive index of cellular components 4. 10 degree light scatter - cell structures or complexity 5. 90 degree light scatter- Lobularity 6. 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 1. Idiopathic thrombocytopenic purpura 2. After splenectomy 3. DIC 4. WAS 5. Aplastic anemia 6. After chemotherapy 7. Sickle cell anemia 8. Heterozygous thalassemia 9. Megaloblastic anemia 10. Myeloproliferative disorders

1. Increase MPV 2. Increase MPV 3. Increase 4. Decrease 5. Decrease 6. Decrease 7. Increase 8. Increase 9. Decrease 10. 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

AUTOMATION Flashcards

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