diagnostic laboratory procedures. microscope use objective lenses 4x, 10x, and 40xobjective lenses...
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Diagnostic Diagnostic Laboratory Laboratory ProceduresProcedures
Microscope UseMicroscope Use• Objective lenses 4x, 10x, and Objective lenses 4x, 10x, and
40x40x• Oil-immersion is used Oil-immersion is used
occasionallyoccasionally• A mechanical stage is necessary A mechanical stage is necessary
to view slides thoroughlyto view slides thoroughly
Microscope UseMicroscope Use
• Viewing area = fieldViewing area = field
Microscope UseMicroscope Use• To scan a slide use 4x to To scan a slide use 4x to
focus, then move to 10xfocus, then move to 10x
• Scan back and forth Scan back and forth overlapping each fieldoverlapping each field
Microscope UseMicroscope Use
Scanning patternScanning pattern
Microscope UseMicroscope Use• Debris can be closely Debris can be closely
examined under high examined under high powerpower
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.
Methods1. Gross exam
- used to observe outward characteristics of the sample.
Methods1. Gross exam
- Several abnormalities can be seen with the naked eye.
Methods1. 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.
Methods2. Direct smear
- A small amount of feces is mixed with water and applied directly to a slide.
Methods2. Direct smear
- The main disadvantage of this technique is that a
small sample may not contain any parasite eggs.
Methods2. Direct smear
- This method also leaves debris on the slide.
Methods3. Floatation
- the most commonly used procedure for diagnosing parasitism.
Methods3. Floatation
- techniques using this method:
- simple floatation
- use of a centrifuge
- Fecalyzer
Methods3. Floatation
Fecalyzer- uses a solution (zinc sulfate or sodium nitrate) that has a specific gravity greater than the specific gravity of most parasite eggs
Methods4. Sedimentation
- is commonly used for eggs that have a high specific gravity
Methods4. Sedimentation - The high specific gravity
of these eggs makes it difficult to use floatation techniques without
distorting them.
Methods4. 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
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