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automated counters


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What machine measures MCV and calculates the hematocrit?
What machine measures Hct and calculates the MCV?
which analyzer does not use light scatter?
Which analyzer has to manipulate eos/basos to differentiate them?
which analyzer has von behren's plates instead of sweepflow?
cell dyn
what is the principle of the cell dyn?
cells are passed between plates with apertures of different size; prefer to flow through the larger, and get counted.
which analyzer uses DC/RF for volume determination and differentiation?
is there a chance of coincidence loss on the cell dyne?
yes; to correct, use pulse editing.
which analyzers seperate a section of cells for hemoglobin via cyanmethemoglobin colorimetry?
all of them
what two ways are white cells counted and differentiated on the cell dyne? (2 acronyms)
WIC - white cell impedence cnt.
WOC - white cell optical count.

the first uses impedence, the second uses light scatter.
what is different between the sysmex 9000 and 3000?
9000 uses DC/RF; the 3000 does not use RF for differentiation, but instead light scattering.
what is cell dyn's claim to faim?
WIC and WOC - two counts based on impedence, and light scatter.
what angles does the cell dyn scatter light?
FAS - forward
orthogonal - 90, right angle
10 - narrow angle
On Celldyn, what does the FAS measurement tell you?
-90 right angle?
-90 depolarized?
FAS = the size of cell
right angle = granularity
depolarized = eosinophils
10 = n:c ratio - nucleus density
what type of sheath fluid is in the cell-dyn?
weak salt that pulls hemoglobin out of cells so there's no interference.
what type of light source is used in the cell-dyn?
polarized helium argon laser.
what is the acronym for the special light scattering used in the cell dyn?
MAPSS - multi angle polarized scatter seperation
what is list-mode analysis?
whatever electrical information is gathered from each cell is given in a direct plot, not a box scatterplot.
which analyzer shows exactly whre basophiles are in the electrical information?
cell-dyn, don't have to rotate the scattergram to visualize them.
what is advia technology based on?

what is it NOT based on?
light scattering
cytochemical staining

not on electrical impedance.
is advia good?
what is it good at?
no; it's unwieldy and difficult to interpret;
give the best RBC information
What do cold agglutinins do to an analysis?
cause RBCs to clump and give an abnormal RBC count;
Hct will be wrong, but Hgb will be normal because cells are lysed.
how do you fix cold agglutinins?
warming the sample and rerun it.
What causes a high take-off?
anything smaller than a lymph.
specific things that cause high takeoff?
-Platelet clumps
-Fibrin strands
if you have nRBCs, what do they do to the analysis, and how do you correct it?
will cause a high-take-off. do a manual diff and correct for the nRBCs.
if you have platelet clumps, how do you correct?
do a manual platelet count.
when the WBC count is over 90000 cells/uL, what happens to the analysis?
How do you correct it?
invalidate the WBC count;
to correct, dilute the sample and rerun it.
if the WBC count is greater than 2% of the RBCs, what does this mean?
You must correct the RBC: subtract two percent of the RBC from the old RBC count for a new one.
What are the effects of a high WBC count?
-falsely elevated HgB (cloudy)
-incorrect RBC and MCV
-Hct must be spun, not calculated.
what stain is used in normal retic counts?
new methylene blue
what occurs in an automated retic counter? (process)
1. cells are stained/incubated.
2. in weak H2SO4, cells lyse, Hgb escapes, and a ghost with precipitated RNA remains.
What are the 2 major types of automated retic counters?
R-3000 by Sysmex;

Advia Retic counter
What type of dye does the sysmex use?
Auromine-O flourescent dye.
what type of dye does the Advia retic counter use?
Oxazine 750
what type of technology does the Advia retic counter use?
Light scattering - at three angles.
What does IRF refer to?
the advia's zones for high and medium staining retics; was used as an indicator of whether a bone marrow graft was successful.
what's the difference btwn the Sysmex and Advia retic counters?
Sysmex - based on flourescent staining.

Advia - based on light scatter.
Which analyzers use electrical impedence for counting?
Which parameter is measured identically in all of the analyzers?
Which analyzers use cytochemical stain?
-Sysmex - for eos/basos
-Advia - for everything.
Which analyzers use NO cytochemical stain?
when would you see a dual-population of cells on the RBC histogram?
in iron def. anemia
a platelet histogram shifting to the right indicates:
platelet clumping and giant platelets.
a RBC histogram that has a high takeoff indicates:

Where would nRBCs be?
schistocytes, platelets.

nRBCs are to the right of normal because they are BIGGER.

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