(M) Week 11: Peripheral Blood Smear Flashcards
Familiarize the roles of the peripheral blood smear
- evaluation of anemia
- evaluation of thrombocytopenia / thrombocytosis
- Identification of abnormal cells
- INfections like malaria, microfilaria
- Inclusions like basophilic stippling, Howell-Jolly bodies, Cabot ring
What is the first thing to consider in making PBS
how to collect the specimen (what specimen is acceptable)
What anticoagulant tube is used for the sample needed for PBS?
EDTA
what does EDTA mean?
ethylenediaminetetraacetic acid
how does EDTA prevent coagulation?
by chelating the calcium
what form of EDTA is more commonly prepared (preferred)
liquid form (easily mixed)
PBS should be prepared within _______ hours of drawing the specimen
2-3 hours
What will be found if a PBS is created with a sample that is more than five hours old
blood cell artifacts
What are the advantages of EDTA samples
- different capacities per tube = multiple slides created
- Slides need not to be prepared immediately
- Prevents platelet clumping
What are the disadvantages of using EDTA sample for PBS
- occurrence of satellitism
- pseudothrombocytopenia (false decrease of platelets)
- Pseudoleukocytosis (false increase of WBC due to platelet agglutinates)
what is the other cause of platelet satelliotosis
platelet specific auto antibody
T or F
in using EDTA blood samples, monocytes can be seen with vacuoles
T
T or F
monocytes visualized with vacuoles will greatly affect the examination of the smear
F (will not effect)
What anticoagulant should be used to prevent platelet satelliotosis
sodium citrate
what is the ratio for blood to sodium citrate
9:1
what is the WBC and platelet count dilution factor?
1:1
what method of blood extraction is used when you need to make the film or smear on the patient’s side
finger / heel puncture (anticoagulated free blood)
platelet clumping is expected when using what anticoagulant
heparinized microcollection tube
When there’s no anticoagulant used, you can only make _____ slides, this is corrected by using _________
few
heparinized microcollection tubes
Familiarize!
Blood smear preparation
- Manual wedge technique / wedge method
- Coverslip method / technique
- Coverslip and slide method
- automated blood smear preparation
most convenient and commonly used method of PBS
manual wedge technique
This is a dispenser of blood for wedge method, it is inserted through the rubberstopper of the tube
Diff-Safe dispenser
What is the advantage of the Diff-Safe dispenser
no need to remove the rubber stopper to obtain a drop of blood
what is the ideal diameter of blood used for PBS
2-3 mm
when the drop of blood is too large, what is the effect on the PBS
long thick film
when the drop of blood is too thin, what is the expected PBS outcome
short thin film
what should the angle be when you are holding the pusher slide
30 to 45 deg angle
What happens to the result of your PBS preparation if you push forward too slowly?
accentuation of poor leukocyte distribution
after smearing the blood, it is fixed with ______ vol / vol of methanol
10% volume
how many slides should be created ?
2 or more film / smear
you may save ___ unstained in cases where another one is needed
1
familiarize the causes of unacceptable PBS
- shows a chip / rough edge on the spreader slide
- when there’s hesitation in forward motion
- the spreader slide is pushed to quickly
- too small drop of blood
- the drop of blood didn’t spread along the width of the slide
- Due to dirt or grease or high lipid level of the patient in their blood
- uneven pressure applied on the slide
- due to time delay
the film is ___________ to ________________ the length of the slide
two-thirds
three-fourths
the film should be _______________ shaped, very slidhtly rounded at the feather edge
finger shaped
thumb
this feature of PBS is very important when examining your film/ smear microscopically
feathery edge
the ________ drop of blood is picked up and spread along the slide
whole
The thickness of the smear is determined by the (enumerate all three)
- angle of the spreader slide
- size of the drop of blood
- speed of spreading
the (greater/lesser) the angle, the thicker and shorter the smear
greater
If the hematocrit is increased, the angle of the spreader slide should be (increased/decreased)
decreased
newborns have (increased/decreased) hematocrit
increased
If the hematocrit is decreased, the angle of the spreader slide should be (increased / decreased)
increased
what causes irregular spread with ridges and long tail in PBS
edge of spreader is dirty / chipped / dusty
what causes holes in film
slide is contaminated with fat / grease and air bubbles
or lipidemia
due to delay in fixing the smear or causes methanol contaminated with water
cellular degenerative changes
this technique is older, rarely used now, more common for blood marrow aspirate smears
coverslip techniue
what materials are needed for the coverslip technique
2 coverslips (22x22 mm)
blood sample
This technique produces an excellent leukocyte distribution, more accurate for differential counting
coverslip technique
what is the disadvantages of the coverslip technique
coverslips are too small (hard to label, transpo, stain, and store)
other name for the coverslip method when used for bone marrow preparation
crush preparation
how will too much pressure affect the performance of the coverslip method?
the film will cause cell rupture
what other material may be used for coverslip technique?
slides
this technique may cause an artifactual increase in lymphocyte counts
wedge smear
greater trauma in cells leads to smudge or _____________ cell formation
basket
what is the more common technique used in the lab (wedge smear / coverslip method)
wedge smear
These are the sample machines that we can use for the so called automated preparation of the film
automated wedge film maker machines
An advanced automated machine wherein both the
staining and making of the smear are done
Coulter LH slide maker and stainer
staining and making of the film can be done every how many seconds?
30
what is the basis of automated machines for making a film?
hematocrit level
type of automated machine that can only do slide preparation (not advanced)
automatic wedge film maker