Lecture 2 - Blood film evaluation Flashcards Preview

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Flashcards in Lecture 2 - Blood film evaluation Deck (33):
1

What should you do to validate the data given by a hematology analyzer?

look at blood film, also gives info that analyzer can't pick up

2

what are 4 things that a machine can't pick up that a trained person can when evaluating blood films

1. RBC morphology: clues to anemia cause
2. WBC morphology: +/- inflammatory or neoplastic dz
3. platelet morphology
4. infectious dz/parasite

3

what tube is preferred for making blood films

EDTA (purple top)

note: green top can be used but causes cells to appear blue/green

4

ideally a blood films should be prepared...

make ASAP after collection (push film or cover slip method)
gently invert the tube 8-10 times
do not heat fix but rapidly dry to prevent artifacts

5

staining blood film with diff-quik stain should let it sit in fixative for __

2 minutes

6

3 romanowsky type stains and what is the most common one

1. diff-quik (most common)
2. wright stain
3. wright-giemsa stain

7

__ is used to stain reticulocytes (anemia) and heinz bodies (oxidative damage)

new methylene blue

8

__ is used to stain iron for BM samples

prussian blue stain

9

using __ will prevent pH changes/funky looking slides

distilled water, but tap water is okay to use if it's the right pH

10

__ is a refractile artifact that can result in moth-eaten appearance and is normally due to poorly maintained quik stains

water artifact (water in fixative)

11

__ is often mistaken for RBC inclusions (parasites like Mycoplasma)

water refractile artifact

12

__ means that when focused up and down on cell the artifact "flashes" in one plane of focus, appearing dark in one while bright in another

refractile

13

After prep and staining the film what should be done

examine grossly for quality of smear, anemia, autoagglutination

14

After examining the slide grossly what is done

evaluate on low (10-20x) then high/oil (50-100x) power

15

big clumps of platelets, large cells, microfilaria and leukocyte inclusions can be seen in what part of the peripheral blood film

feathered edge (rainbow region)

16

where should you count on peripheral blood film

monolayer, middle between the feathered edge and the base where the RBC are spread out and WBC are easy to see

17

__ is the first part of the blood film examined on low power

feathered edge (look for platelet clumps and microfilaria) do not use for counting!

18

__ in the feathered edge are excessively spread and appear larger than they should, a lot of cells are also smudged here

leukocytes

19

RBC in the feathered edge are completely flattened and lack a central pallor which mimic __, abnormal shapes are hard to ddx in this area

spherocytes

20

what 4 things do you look for in the monolayer

1. platelet estimate
2. WBC estimate and differential
3. morphologic eval of ALL cells
4. data validation

21

The coverslip method makes one big __ layer

monolayer

22

in the __ layer about on 10x field behind the feathered edge the RBC are spearated or barely touching/not overlapping and the WBC are uniformly distributed

monolayer

23

First step to systematic blood film eval is

view on low power in a good area to confirm cell counts, assess dom WBC, and look for "big" things

24

leukocyte clumping is called __, automated WBC count falsely decreased by this

leukergy

25

most machines won't report __ such as the "big blue uglies"

atypical WBC (BBU are immature lymphocytes)

26

On high power look for WBC and Platelet #/morphology and what 5 RBC things (only a human can do these things!!!)

1. arrangement
2. size
3. shape
4. color
5. inclusions

27

Normal min amount of platelets/100x field in dogs and cats

7-10

28

to estimate platelet count

multiply the average # of platelets for 10 fields then multiply by 20,000/mcL

29

large platelets suggest __ but can be normal for

BM production
normal: felids and cavalier king charles spaniels (macrothrombocytopenia is normal for these)

30

how many WBC should be counted on high power for a WBC differential

200

31

what 4 morphological features of WBC are looked for on high power (only a human can do these!!!!)

1. neutrophil - left shift or toxicity
2. lymphocyte and monocyte reactivity
3. parasites
4. atypical or neoplastic cells

32

to estimate WBC

on 100x: average # (at least 10 fields) x 10,000 = WBC/mcL

33

if using an objective other than 100x how do you estimate WBC

average #wbc x Square of the objective power used to do the count. (for 100x = 10,000)