Diagnostic
Laboratory
Procedures
Microscope Use
• Objective lenses 4x, 10x,
and 40x
• Oil-immersion is used
occasionally
• A mechanical stage is
necessary to view slides
thoroughly
Microscope Use
•Viewing area =
field
Microscope Use
• To scan a slide use 4x to
focus, then move to 10x
• Scan back and forth
overlapping each field
Microscope Use
Scanning pattern
Microscope Use
• Debris can be closely
examined under high
power
Sample Collection
• The animal owner will
most often collect the
stool sample.
Sample Collection
• The sample should be
fresh since some
parasite eggs become
unrecognizable as the
feces ages.
Sample Collection
• If a fresh sample
cannot be obtained,
one can be
refrigerated, but for no
longer than 24 hours.
Methods
1.Gross exam
- used to observe
outward characteristics of
the sample.
Methods
1.Gross exam
- Several abnormalities
can be seen with the
naked eye.
Methods
1.Gross exam
- observe and record
• color and consistency
• blood and mucus
• age of sample
• presence of adult
parasites
Methods
2. Direct smear
- the fastest and
simplest method of
diagnosing
parasitism.
Methods
2. Direct smear
- A small amount of feces
is mixed with water and
applied directly to a
slide.
Methods
2. Direct smear
-The main disadvantage
of this technique is that
a
small sample may
not contain any parasite
eggs.
Methods
2. Direct smear
- This method also
leaves
debris on the
slide.
Methods
3. Floatation
- the most commonly
used procedure for
diagnosing parasitism.
Methods
3. Floatation
- techniques using this
method:
- simple floatation
- use of a centrifuge
- Fecalyzer
Methods
3. Floatation
Fecalyzer
- uses a solution (zinc
sulfate or sodium nitrate)
that has a specific gravity
greater than the specific
gravity of most parasite
eggs
Methods
4. Sedimentation
- is commonly used for
eggs that have a high
specific gravity
Methods
4. Sedimentation
- The high specific gravity
of these eggs makes it
difficult to use floatation
techniques without
distorting them.
Methods
4. Sedimentation
- Sedimentation allows
eggs to sink to the
bottom.
Debris
• may be easily confused
with parasite eggs.
Common Debris:
• hair
• plant
material
• air bubbles
•fat
•epithelial
cells
•pollen grains