Automation Flashcards
Also known as “Coulter principle”
Electrical impedance principle
Changes in _____________ produced by a particle as it passes through a small aperture
electrical impedance (resistance)
Display the pulses that are generated by the cells as they interrupt the current
Oscilloscope
Principle of Oscilloscope
of pulses generated = # cells
height of the voltage pulse is directly proportional to the volume of the cell, (which allows discrimination and counting of cells of specific volumes through the use of threshold circuits.)
depicts the volume distribution of the cells counted
Volume distribution Histogram
_________ of the electrical pulse produced indicates the cell’s volume
Amplitude (magnitude)
separate the cell populations on the histogram, and the count is the cells enumerated between the lower and upper set thresholds for each population
Volume threshold
What are the volume thresholds for
RBC
WBC
PLatelets
- 24-36 fL
- 30-35 fL
- 2-20 fL
sample stream is surrounded by a sheath fluid as it passes through the central axis of the aperture
Hydrodynamic Focusing
__________ allows the central sample stream to narrow sufficiently to separate and align the cells into single file for passage through the sensing zone
Laminar flow
Which CBC parameter is not being directly measured?
Hematocrit determination
Two methods of acquiring hematocrit determination
- HCT = (RBC x MCV)/10
- Cumulative RBC pulse height detection
Determined using a high-frequency electromagnetic probe that provides information on the cells’ internal constituents
Radiofrequency conductivity
Resistance to a high voltage electromagnetic current flowing between both electrodes simultaneously
RF resistance
cell interior density is proportional to ______________
pulse height or change in the RF signal
simultaneous measurement of multiple physical characteristics of a single cell as the cell flows in suspension through a measuring device
Flow Cytometry
number of pulses generated is directly proportional to the ________________
number of cells passing through the sensing zone in a specific period
_________ of the electrical pulse produced indicates the cell’s volume
Amplitude (magnitude)
Key advantages of flow cytometry in comparison to impedance
- can be coupled with immunofluorescence
- provides more specific and accurate results
Angles of light scatter
0° forward angle
10° light scatter
90° light scatter
Depolarized 90°
- Cell size
- Cell structure & complexity
- Lobularity (granulocyte)
- Resolves Eosinophils because of their crystalline granularity
is a numerical or graphical boundary that can be used to define the characteristics of particles to include for further analysis
Gate
is a process in selecting an area on a scattergram generated during the flow experiment
Gating
Explain the results of quadrants
Q1:
O2:
O3:
O4:
- (+)
- (++)
- (– –)
- (+)
General Characteristics of Histogram
- Symmetrical bell-shaped or Gaussian distribution
- Flattened curve –> Increase SD
- Depict the presence of subpopulations
Conditions that causes decreased MPV
- Aplastic anemia
- megaloblastic anemia
- Wiskott-Aldrich syndrome
- After chemotheraphy
Conditions that caused increased MPV
-idopathic thrombocytopenic purpura
- after splenectomy
- sickle cell anemia
an increased in mean platelet volume denotes?
presence of giant platelets
*Produce by the machines as indicators if there is something wrong with measurements or analysis
*Abnormal Curve in front of lower discriminator
AG Flag
Deviation on upper discriminator curve in Leukocyte histogram
WU Flag
Causes for WU Flag
Extreme leukocytosis
Rare: WBC aggregation
refer to the level at which the machine can measure the particular analyte
Linearity
Abnormal height at upper discriminator in Platelet Histogram
UD Flag
Possible causes for UD flag?
- Platelet clump (clotted sample, EDTA compatability)
- Giant platelets
Micro RBCs
Inclusions for Electrical impedence report
- CBC results
- Scattergram
- Histogram
- Flagging
Instrumental errors
Negative:
Positive:
- Excessive lysing of RBC
+ aperture plugs, Extraneous electrical pulses, Bubbles
