automated analyzers (wk 11 study questions)

Question 1

3 benefits to the practice for using automated analyzers

Answer 1

Reduced labor costs
More complete information
Improved data reliability

Question 2

Which of the automated cell counts are least accurate, RBC, WBC or Platelet?

Answer 2

platelet

Question 3

Polycythemia

Answer 3

Increased number of RBCs; Accompanied by increased PCV and hemoglobin concentration

Question 4

Anemia

Answer 4

Decrease in the oxygen-carrying capacity of the blood

Question 5

three categories of analyzers

Answer 5

Impedance
Laser Flow Cytometry
Quantitative Buffy Coat Analysis System

Question 6

Why should the CVT run regular quality control measures on the analyzer?

Answer 6

to ensure accuracy

Question 7

Explain how impedance is used to count cells and how the machine can tell
an RBC from a WBC using this method

Answer 7

 Passage of electric current across two electrodes separated by a glass tube with a small opening or aperture
 Electrolyte fluid conducts the current.
 Counting by moving a specific volume of cells in the electrolyte solution through the aperture by use of a vacuum or positive pressure
 Cells are poor conductors and impede the flow of the current
 Change in current is a function of cell size

Question 8

disadvantages to using the impedance analyzer

Answer 8

Variation of cell size
Morphologic abnormalities not noted
Platelet clumping inaccuracies
Nucleated RBC inaccuracies

Question 9

Quantitative Buffy Coat analysis system and its limitations

Answer 9

-Uses differential centrifugation and staining to estimate cells
-Uses specialized microhematocrit tube.
-Gives hematocrit value and estimates WBC and platelet concentrations
Limitation:
-Groups granulocytes and agranulocytes
-Left shift and Lymphopenia may go undetected
-Provides only estimates

Question 10

Laser-based flow cytometer

Answer 10

Uses focused laser beams to evaluate the size and density; Cells scatter light differently

Question 11

When would manual cell counts be performed?

Answer 11

avian and exotic practices

Question 12

three advantages for running a CBC using the automated analyzer

Answer 12

-Faster than manual counts
-No operator bias
-More reproducible: counts more cells than manual
-Little training needed

Question 13

disadvantages of running a CBC on the automated analyzer

Answer 13

-Clots, large platelets, and Nucleated RBCs can cause errors
-Can not pick up diagnostic changes in cell morphology

Question 14

When should a blood smear be made and examined for a patient sample?

Answer 14

Recommended for all CBCs but definitely for sick patients

Question 15

hematology analyzers

Answer 15

Impedance method:
-Cells pass through a charged aperture, disrupting the current
-Each interruption is counted
-The length of the interruption is proportional to cell size
-Chemical lysing agents are also used to help differentiate the cells

Question 16

What are the graphs called that are shown on the results screen?

Answer 16

histogram

Question 17

Dot plot

Answer 17

A visual representation of the CBC

Question 18

What does the size and shape of the cloud on a dot plot tell us?

Answer 18

an indication of whether the cells of one type (i.e. the RBCs) are all similar in size or abnormally varied

Question 19

What would the RBC dot plot look like if the patient was anemic?

Answer 19

very small

Question 20

What would the WBC dot plot look like if the patient had neutrophilia?

Answer 20

larger

Question 21

What can the dot plot tell you about abnormal cell morphology?

Answer 21

size only

Question 22

doublets

Answer 22

Two discreet red blood cells that are in close proximity to one another when they are examined by the laser beam; mapped as one event but counted as two cells

Question 23

RBC fragments

Answer 23

-Portions of red blood cell membranes from broken cells
-Particles have a similar size to platelets but refract light differently and are therefore located to the left of the platelet population
-Colored pink

Question 24

uRBC

Answer 24

Unlysed RBC (colored orange)

Question 25

qualiBeads in the Lasercyte

Answer 25

Each CBC5R tube contains a known quantity of standard-sized particles called
QualiBeads. Quality assurance check for each individual run. If too few or too many QualiBeads, the sample run will be flagged

Question 26

Explain how to load the Lasercyte to run a sample

Answer 26

3 mL tube
invert 8 times
remix sample prior to testing
place CBC5R tube in slot 2
place sample in slot 1
close lid and run

Question 27

Platelet clumping can cause an error in the RBC count. Do you think the RBC
count will be too low or too high?

Answer 27

too high-recognized as RBC
therefore increased RBC count

Question 28

Platelet clumping will also cause an error in the platelet count. Will it be too low
or too high?

Answer 28

Too low as platelets will not be counted