BIOT 309: BLOOD SMEAR
PRACTICAL
Feb., 2013
Microscopic
Views
Fish Blood
Bird Blood
Horse Blood
Frog Blood
Cat Blood
Dog Blood
Human Blood
Snake Blood
ASH Teaching Slides: Blood Cells
Normal blood smear. The four larger cells shown are called
granulocytes, a type of white blood cell.
Maslak, P. ASH Image Bank 2008;2008:8-00067. Copyright ©2008 American Society of Hematology.
Photomicrograph of a Blood Smear
Figure 10.2
Cells you will see
• Red blood cells, erythrocytes, no nucleus,
transport O2
• Platelets, deliver fibrin
• White blood cells, leukocytes: complete
cells with a nucleus and organelles,
defenders against disease,
Cell Differentiation and Lineages
• Granulocytes
– Granules in their
cytoplasm can be
stained
– Include neutrophils,
eosinophils, and
basophils
Figure 10.4
Eosinophiles
• Function: Phagocytosis of
antigen-antibody
complexes; allergens
• Release enzymes to weaken
or destroy parasites such as
worms.
• Appearance: Nuceus has 2
large lobes
Basophil
• Appearance:
• Function: Secretes
Histamine,( a
vasodilator)
• Secretes heparin ( an
anticoagulant)
Neutrophils
Appearance
• Nucleus usually with 35 lobes in S-C shaped
array
Functions:
Phagocytosis of bacteria
Release of antimicrobial
chemicals
Peripheral Smear Preparation
Precaution: You need the right size drop to get a
good smear
• Too large drop = too thick smear  too many
cells
• Too small drop = too thin smear  too few cells
• Thick and thin also depend on (de)hydration,
hematocrit (anemia)
Peripheral Smear Preparation
2. The pusher slide is
held securely with the
dominant hand in a
30-45 deg angle.
- quick, swift and
smooth gliding motion
to the other side of
the slide creating a
wedge smear
Peripheral Smear Preparation
Peripheral Smear Preparation
Precautions:
Ensure that the whole drop of blood is picked
up and spread
Too slow a slide push will accentuate poor
leukocyte distribution, larger cells are
pushed at the end of the slide
Maintain an even gentle pressure on the slide
– not doing so leads to ridges and valleys
Keep the same angle all the way to the end of
the smear.
Peripheral Smear Preparation
• Allow the blood smear to thoroughly dry – thicker will
take longer
• Fix the blood smear with 70% methanol for 5 seconds;
blot slide edge: let surface thoroughly dry
• Stain cells with Giemsa or Wright stain for 5’ - both are
available; write in notebook which one you use – they
color cells differently
• Dip slide in distilled water, 3 – 5 times
• Blot edge; thoroughly dry
You are now ready to observe
without and with microscope!!!
Feature of a Well Made Wedge Smear
• Smear is 2/3 or ¾ the entire slide
• Smear is finger shaped, very slightly rounded at
the feathery edge: widest area of examination
• Lateral edges of the smear visible
• Smear is smooth without irregularities, holes or
streaks
• When held up in light: feathery edge should show
rainbow appearance
• Entire whole drop of blood is picked up and
spread
• See shape, internal morphology, comparative
size, count cells, identify disease conditions
Peripheral Smear Examination
•
Visual – no microscope: record in lab notebook
–
–
–
•
•
Accurately draw both smears
Measure length and width in mm
•
•
Assess overall quality, i.e.,
Does it have a feathery edge? Fingerprint shape?
Quality of the staining –also assess at
Microscopic:
10x Objective record in lab notebook
–
•
•
•
Observe types and distribution of the cells – use
systematic approach, i.e., serpentine
where do you find red blood cells; are they easily
distinguished, i.e., separated
Check lateral edges for WBC (white blood cells)
distribution; do you see them distinctly
Quick sketch of 2 different fields; label and describe cells
Choose the best areas for assessment
• Systematic search
• Back and forth serpentine or battlement
track patterns are preferred – move the slide
mount
Peripheral Smear Examination
•
•
Microscopic:
40x Objective this week and next
1. Determine correct area to view – cells spread
apart but not too much
Optimal Assessment Area:
1. RBCs are uniformly and singly distributed
2. Few RBC are touching or overlapping
3. Normal biconcave appearance
Peripheral Smear Examination
• Too thin
Too thick
Assessment at 40X
• Pick 5 fields that show different types of cells
and sketch all cells; describe these cells in
your own words
• Determine which cells you are seeing
Before you leave at 9:50
• Make sure your slides have your student ID#
• Give to Younis; he will save for next week
• Clean up your area
Final Assessment – Next Week
• Microscopic:
• 100x objective, oil immersion