Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Clinical Pathology > Unit 2 > Flashcards

Unit 2 Flashcards

1
Q

Define the following prefixes/suffixes

A

Cytosis/philia: increased cell numbers

Penia: decreased cell numbers

Macro: bigger than normal

Micro: smaller than normal

Normo: normal

Poly: increase

Hypo: decreased

Hyper: increased

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Cell count can be performed manually or with __

A

Automated analyzers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Whose cell counts are normally done manually

A

Exotic and avian species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the 3 blood cell analyzer categories

A

Impedance analyzers

Laser flow chrome try analyzers

Quantitative Buffy coat analyzers

(Some are combinations of these)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Which type of blood analyzers are most common

A

Impedance analyzers and laser flow cytometry analyzers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How does the impedance analyzers classify cells

A

Based on their size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does the impedance flow analyzer work

A

A electric current passes across two electrodes that are separated by a glass tube that has a small opening m

A specific volume of cells in the electrolyte solution is passed through the opening of the glass tube )by vaccine or positive pressure)

Cells do not conduct electricity so they impede flow while passing through the opening

Small changes in current are counted to determine the blood cell concentration

The size of the cell is proportional to the change in current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Can impedance analyzers differentiate between cell types? When can it not?

A

Yes

May be in accurate in cats (similar RBC and platelet size) and not reliable in exotics (cell size too similar)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is it called when cell size information is displayed in a graphical format of the cell Population

A

Histogram

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Why are lysing agents used in WBC counts

A

Lyses platelets and RBCs therefore they are not counted

(May still lyse WBCs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Is a lysing agent used to count RBCs

A

No but they are counted at a higher dilution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Can impedance analyzers also determine Erythrocyte size? What else can it determine about RBCs

A

Yes

Cell volume, packed cell volume, MCV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are some disadvantages of the impedance analyzers

A

Variation of cell size produces errors

Does not identify morphological abnormalities

Nucleated RBCs, large platelets and platelet clumping create inaccurate results

These machines Require daily cleaning (dust affects results)

Blood must be warmed to room temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How do laser flow cytometry analyzers work

A

Used focused laser beams to evaluate size and density of cells

Cells scatter light differently depending on their shape, volume, number and size of granules and nuclei

Cells flow past the later in single file and how the light is refracted and picked up on the other side of the tube determines the cell type

May use dyes to help further classify cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How do quantitative Buffy coat analyzers work

A

Used centrifugation and staining to estimate cellular elements

The buggy coat layer is expanded within a hematocrit tube with a specialized bead

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What do Buffy coat analyzers provide

A

A hematocrit value, estimate of leukocyte concentration and platelet concentration

Gives partial differential counts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the limitations of a quantitative Buffy coat system

A

Abnormalities may be undetected

18
Q

True or false
Buffy coat systems should only be used as a screening test

A

True

Only provides estimates of cell numbers, not actual counts

19
Q

What is a histogram

A

A visual representation of the number and size of cell types present in a sample

Size on X axis, numbers in the y axis

May be in a scatter plot form

20
Q

What does a histogram determine

A

Average size of cells
Distribution of cell size
Detects sub-populations
Evidence of anomalies

21
Q

True or false
Histograms are diagnostic

A

FALSE
should only be used as a screening for pathology (must still look at a blood film)

Or used as a quality control measure

22
Q

What is a total leukocyte count

A

Uses a specified volume of blood to count the total number of WBCs

Results written as: #of WBC x10^9/L to one decimal place

23
Q

How useful are total leukocyte counts by itself

A

Not very useful

Must be combined with the % from the differential count

24
Q

How are total leukocyte counts performed

A

Leukoc-tic system (manual counting using a blood diluting solution and an hemocytometer)

or with automated analyzers (may use same blood diluting solution)

25
Q

What is a WBC estimation

A

Used as a quality control measure for both manual and automated counts

Estimation of the total WBC count is done with the differential blood smear

(#WBC/high dry fields) x2= #WBCx10^9/L

26
Q

What are the 4 steps of interpreting a leukogram

A

1) look at the total leukocyte concentration (this is used to calculate absolute differential conc. (Total leukocyte conc. x cell type % differential count)

2) look for morphological abnormalities

3) look for abnormal cell types (1-2% is not reported)

4) look for immature cell stages

27
Q

What is one think that can cause automated analyzers to report artificially high total leukocyte counts

A

Counting nucleated RBCs

28
Q

What are the 3 types of chemistry analyzers, which is most common?

A

Photometry (most common)

Electrochemical

Light-scatter techniques

29
Q

How does photometry chemistry analyzers work

A

Machine is a spectrophotometer: produces light of various wavelengths, Designed to measure the amount of light transmitted through a solution

Components: light source, prism, wavelength selector, photo detector, read out device

30
Q

What are the two most common techniques used in photometry chemistry analyzers, describe each

A

Absorbance: how much light did not reach the detector (uses wet/rotor technology)

Reflectance: how much light was reflected off a test substance (used by most in-house analyzers, uses a dry/slide chemistry system)

31
Q

How does photometry analyzers detect results

A

We know how much light was produced, and how much light passes through the solution to the detector, we can calculate the light absorbed by the analyte

High conc. Of the analyte: more light is absorbed by the analyte and less reaches the detector

Low conc. Of analyte: less light is absorbed by the analyte and more reached the detector

32
Q

What are the two types of absorbance assay methods used in photometry analyzers

A

End point: measures the concentration of pre-existing substances in the serum or plasma, involves a chemical reaction that reaches a stable end point and measures a color change

Kinetic: generally used to measure enzyme assays or when enzyme based reagents are used. Reaction results are measured at specific time after the initiation of the reaction. Does NOT reach a stable end point

33
Q

How does temperature affect enzyme activity, what temperature are most assays performed at

A

Inhibited by low temps

Accelerated by high temps

Most done at 30-37 degrees C

34
Q

How are enzymes denatured

A

Enzymes are proteins: denatured by temperature, pH extremes, organic solvents, heavy metals or physical damage

35
Q

How do electrochemical chemistry analyzers work (AKA ion selective electrode technology -ISE)

A

Most commonly used to measure electrolytes, also referred to as potentiometers

Reference electrodes interact with only one type of ion and contain a known concentration of that ion

The sample interacts with a second ion specific electrode in a biosensor reagent strip or cartridge

The two electrodes create a voltage difference which is used to calculate the concentration of the ion in the sample

The difference in electrical potential between the electrodes is proportional to the concentration of the ion in the sample

36
Q

What is Potentiometry

A

Measure the electrical potential between two electrodes

37
Q

How do light scatter chemistry analyzers work

A

Used to measure the concentration of larger molecules in fluid (immunoglobulins, antigen-antibody complexes, drugs, etc)

Detects the reduction of the intensity of a light as it passes from the light source through a solution

38
Q

What are dry systems used in automated analyzers

A

Include systems that use reagent impregnated slides, pads or cartridges

Most use reflectance photometry

39
Q

What are some benefits of dry systems, what are some limitations.

A

Little to no handling/storage concerns
Can perform individual or single assay tests
Allows for loading of a large number of slides at once which reduces time

A bit more expensive to run
Sample rejection is common esp with lipemia, hemolysis and large animals

40
Q

What are liquid systems used in automated analyzers

A

Systems that use lyophilized reagent or already prepared liquid reagent

Most common is the lyophilized rotor technology (rotor is made of individual cuvettes that diluted sample Is added to

May also use bulk reagents: can run individual tests, reagent may or may not need to be diluted, extensive maintenance)

41
Q

What are some benefits and limitations with liquid systems

A

Quite accurate

Cannot run individual tests
More handling/storage concern (more expensive systems may have less handling concerns)

42
Q

What are dedicated use analyzers

A

Most utilize electrochemical methods

Test for a specific substance (only one substance)

Ex. Blood glucose monitors

Clinical Pathology (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions