AUTOMATION IN HEMATOLOGY Flashcards
Fresh whole blood anticoagulated with EDTA (ethylene diaminetetracetic acid) [purple/lavender top tube]
The tube should be ___ full
The tube should be mixed/inverted _ to _ times to adequately mix the blood with anticoagulant and hence inhibit clotting.
Storage: Refrigerated at __ until needed and allowed to reach room temperature before testing.
6 to 8
1/3 full
4°C
Plasma should be ____ and fairly ___
If the plasma is ___, ___ ___ (hemolysed), this will interfere with accurate testing and must be redrawn or dealt with accordingly in testing.
Some hematology tests require ___ blood () or __ ()
pale yellow. clear
dark yellow, milky or red
heparinized (green top) serum (red top)
-
Preserves cell function
Preserves cellular morphology
For accurate counts, the test should be done within __, because in time, cells begin to change.
If the patient’s cells are altered by EDTA, ____ can be used if the blood is tested within a few hours.
2 hours sodium citrate (blue top)
Mission of the Hematology Laboratory
Provide ___
test results that reflect the condition within the body (in vivo), and not the changes that took place once the blood was removed from the patient and placed in a glass tube (in vitro)
Mission of the Hematology Laboratory
Correlate ____
results from all test information (puzzle pieces) available to provide the primary health provider with a clear and accurate picture of the patient’s state of health.
is a routine test
CBC
The automated CBC report includes:
- R
- T
- A S
- A P
- P
- H
- H
- R
- R
- M
Red blood cell count with a histogram and morphologic indices Total WBC count with a histogram A scattergram for differentiating leukocytes A platelet count with a histogram Platelet morphologic index Hemoglobin level Hematocrit RBC indices Reference ranges Markers/Flags for out of range values
Each laboratory must establish its own reference ranges due to variation in instrumentation, procedures, and local populations which may render the generic normal values less accurate for the specific laboratory involved in the testing
Each laboratory must establish its own reference ranges due to variation in instrumentation, procedures, and local populations which may render the generic normal values less accurate for the specific laboratory involved in the testing
PRINCIPLES INVOLVED IN AUTOMATIONELECTRONIC IMPEDANCE
-
-
Cell-Dyn 3000 (Abbott)
Sysmex NE 8000 Cell Counter (Baxter)
COBAS Cell Counter (Roche)
PRINCIPLES INVOLVED IN AUTOMATIONELECTRONIC IMPEDANCE
Basic Procedure:
Dilution of the __ whole blood specimen in an electrolyte solution such as __. The __ suspended in this fluid are POOR conductors of electricity, whereas the __ is a GOOD conductor of electricity. The dilution must allow an adequate number of cells to count without a concentration so high that more than once cells goes through the aperture at once (_____). If more than one type of cell (___) is present in the sample, it may be necessary to __ or __ them to get the accurate count of the other.
Electrodes are located on either side of the counting orifice or path. An electrolyte solution is placed between the electrodes and a flow of electrical current is established.
EDTA saline cells solution coincidence error particle lyse or remove
PRINCIPLES INVOLVED IN AUTOMATIONELECTRONIC IMPEDANCE
Basic Procedure:
A specific amount of solution is pulled through the aperture. Any particle (cell) that passes through the aperture will momentarily____the resistance of (or interrupt) the electrical flow between the electrodes generating a __, which can be counted, measured, and displayed on a screen.
The size of the resistance is proportional to the size of the cell. From this information the counter computer can provide an accurate count and size of the particle.
A background (quality assurance) check is obtained by first counting any miscellaneous particles within the vial of saline that may be erroneously counted as cells. This background should be VERY LOW.
Controls or standards must also be counted to ensure accuracy of the data generated. This should be a specimen of known value.
All specimens should be run at least in duplicate and most instruments do three to five determinations on each specimen to ensure the precision of the data generated
INCREASE
PULSE
PRINCIPLES INVOLVED IN AUTOMATIONELECTRONIC IMPEDANCE
Basic Procedure:
_______ is proportional to the size of the cell. From this information the counter computer can provide an accurate count and size of the particle.
The size of the resistance
PRINCIPLES INVOLVED IN AUTOMATIONELECTRONIC IMPEDANCE
Basic Procedure:
A ______ is obtained by first counting any miscellaneous particles within the vial of saline that may be erroneously counted as cells. This background should be ___.
background (quality assurance) check
VERY LOW
PRINCIPLES INVOLVED IN AUTOMATIONELECTRONIC IMPEDANCE
Basic Procedure:
___________ to ensure accuracy of the data generated. This should be a specimen of known value.
Controls or standards must also be counted
PRINCIPLES INVOLVED IN AUTOMATIONELECTRONIC IMPEDANCE
Basic Procedure:
___________ and most instruments do ___ to ___ determinations on each specimen to ensure the precision of the data generated
All specimens should be run at least in duplicate
three to five
Is the methodology used by some Coulter instruments to characterize cells for the scattergrams.
PRINCIPLES INVOLVED IN AUTOMATION
LASER SCATTERING
___ is utilized for cell counts as well as cell characterization by FLOW CYTOMETERS.
Laser light scatter
-
-
Technicon H-3
Cell Dyn 3000 (Abbot)
Serono Diagnostics System 9000
PRINCIPLES INVOLVED IN AUTOMATION LASER SCATTERING
The sample is diluted in the instrument into a stream of fluid containing the cells to be counted in a single cell flow
(HYDRODYNAMIC FOCUSING)
PRINCIPLES INVOLVED IN AUTOMATIONLASER SCATTERING
The cells pass through a ___ on which a light is __. As the cell passes through the light path, it scatters the light in all directions.
A ______ senses and collects this light “scatter information” and transforms it into digital information, which provides “characteristic information about the specific cell as it passes through the flow cell.”
Traditional flow cytometers uses _____ and _____ to differentiate__ ___ ___
flow cell
focused
photodetector
FORWARD LIGHT SCATTER (0 degrees) and ORTHOGONAL LIGHT SCATTER (90 degrees)
lymphocytes, monocytes, and granulocytes.
PRINCIPLES INVOLVED IN AUTOMATIONLASER SCATTERING
The ____ uses two additional dimensions of light scattering to accurately separate the cell characteristics.
This is called _______ and involves the use of __________ (10 degrees) to resolve ___ and ___ (90 degrees) to resolve ____.
This eliminates the need for cytochemical staining or monoclonal tagging to identify these cells.
CELL-DYN 3000
MULTIANGLE POLARIZED SCATTER SEPARATION (MAPSS)
narrow-angle light scatter (10 degrees)
BASOPHILS
depolarized light scatter
EOSINOPHILS
Is used along with light scatter.
PRINCIPLES INVOLVED IN AUTOMATION LIGHT ABSORBANCE
Instruments using LIGHT ABSORBANCE:
Sysmex 8000
COBAS
Technicon H-3
PRINCIPLES INVOLVED IN AUTOMATIONLIGHT ABSORBANCE
______ which requires a _____ to count and classify leukocytes.
Specifically stains the cells of interest
darkfield optical system
Procedure is similar to light scatter, but the detection system is different.
LIGHT ABSORBANCE
Light is scattered through the opening around a darkfield disk as cells passes through the sensing zone, one at a time. The light scatter is measured by a photodetector and is related to the cell number.
If the cells is stained, some of the light will be ______________. The use of various specific cell stains, a differential count can be done.
LIGHT ABSORBANCE
absorbed proportional to the amount of staining
Used to identify an alteration in cell number, size, and some internal characteristics.
provide the number of cells in one axis and the cell size on another axis.
Leukocytes of histograms and scattergrams