Ch 50 Diagnostic Techniques Flashcards
What is the ideal condition for samples in parasitology?
Samples should be as fresh as possible.
Fresh samples increase the accuracy of diagnostic techniques.
What information should be included on a sample label?
Client name, date of collection, species, animal identification.
Proper labeling is crucial for tracking and identifying samples.
What precautions should be taken while handling samples?
Wear gloves and protective outerwear, wash gloves frequently, clean and disinfect work areas and equipment.
These precautions prevent contamination and ensure personal health.
What is the most reliable method for detecting parasitic infections?
Microscope.
A binocular microscope with multiple objectives is typically used.
What are the objectives typically found in a binocular microscope for parasitology?
x10, x40, and x100 objectives.
Different magnifications allow for detailed examination of specimens.
What is the initial step in evaluating fecal specimens?
Begin with a gross examination of the sample.
Examination includes assessing consistency, color, presence of blood, mucus, odor, and adult parasites.
What is a direct smear in fecal examination?
Simplest method requiring minimal equipment to visualize trophozoite stages of protozoal parasites.
Example: Giardia.
What is the disadvantage of a direct smear?
Small sample size and debris may be confused with parasitic material.
This can lead to inaccurate diagnoses.
What is fecal flotation based on?
Differences in specific gravity of life cycle stages of parasites.
Ova float to the surface while some eggs sink based on their specific gravity.
What is the purpose of centrifugal flotation?
More sensitive than simple flotation and recovers more eggs and cysts in less time.
It requires a tabletop centrifuge.
What is fecal sedimentation used for?
When suspected ova are too large to be recovered with standard flotation.
Useful for fluke ova.
What is the Baermann technique used for?
To recover larvae from fecal samples.
Particularly used for lungworm infections.
What is the modified McMasters technique used for?
Provides an estimate of the number of eggs or oocysts per gram of feces.
Mainly used in livestock and horses.
What staining procedures are commonly used in parasitology?
Lugol iodine, new methylene blue, Diff-Quik, Wright or Giemsa stain.
Stains help with identification of protozoal parasites.
What can evaluation of blood samples reveal?
Adult parasites or various life stages either free in the blood or in the blood cell.
Thick or thin smears are prepared for examination.
What is the direct drop method in blood evaluation?
A drop of anticoagulated whole blood is examined microscopically.
It is the simplest blood evaluation method.
What does the modified Knott test help differentiate?
Dirofilaria and Acanthocheilonema.
It focuses on body width, body length, and shape of the cranial end.
What are immunologic and molecular diagnostic tests used for?
To identify antigen and/or antibody to specific parasites.
Examples include tests for canine heartworm and Toxoplasma.
What is the purpose of cellophane tape preparations?
To recover external parasites that live on the surface of the skin.
Samples can be collected from various body areas.
What are some methods to examine fecal specimens?
Gross examination, direct microscopic examinations, fecal flotation, centrifugal flotation, and sedimentation.
Each method provides different insights into parasitic infections.
