Parasite Examination Flashcards
(26 cards)
Physical examination; based on signs
and symptoms of the patient/s exhibited.
Clinical Diagnosis
Based significantly on laboratory reports
or test results
Laboratory Diagnosis
- Important procedure in evaluating a
disease by providing evidence of a new or
unsuspected etiologic agent - Able to confirm a clinical impression that
the condition has a parasitic nature
-Aids the physician with the appropriate
medication and helps in monitoring the
effect of a treatment regimen.
Laboratory Diagnosis
Successful laboratory identification of
parasites requires the knowledge and
practice of laboratory testing in the
pre-analytic, analytic, and post-analytic
steps.
What happens in Pre-analytic testing
- Specimen Collection
-Transport - Labeling
What happens in Analytic testing
Specimen Processing
Post-analytic
- Interpretation
- Reporting of results
the two methods for identifying parasite infections
➢ Serologic test
➢ Microscopic
the most common procedure performed in
the area of parasitology
Ova & Parasites (O&P) Examination
Two general components associated with
routine parasitology:
A. Macroscopic Examination
B. Microscopic Examination
Typical stool collection protocol consists of…
three specimens, one specimen collected
every other day or a total of three
collected in 10 days.
In the diagnosis of amebiasis, up to ______ specimens in _____ is acceptable.
six specimens in 14 days is acceptable.
Therapy that includes anti-diarrhea,
laxatives, barium, bismuth, or mineral oil
should be collected before therapy or not
until ________
5 to 7 days after the completion of therapy.
Collection of specimens from patients who
have taken antibiotics or antimalarial
medications should be delayed for ________
2 weeks following therapy.
Specimens should be collected in a ________
clean, watertight container with a tight-fitting lid
The acceptable amount of stool required
for parasite study is ______
2 to 5 g, often referred to as the size of a walnut.
Criteria for specimen rejection
- Urine contamination
- Water contamination
- Stools retrieved from the toilet bowl
- Toilet paper in the stool specimen
- Specimen container has NO LABEL
What should be done when sampling handling?
-Gloves and a protective coat should be
worn at all times
-Universal precautions
What is the time frame
➢ Fresh specimen – to demonstrate the
motility of the protozoan trophozoites.
➢ Liquid specimens = within 30 minutes
➢ Semi-formed specimens- 1 hour .
➢ Formed stool - 24 hours
Recommended ratio is three parts fixative
to one part stool
1:3 ratio
Fixatives are substances that ______ the
morphology of protozoa
Preserve and prevent further development
The specimen must be fixed in the
preservative for at least _____
30 mins
Describe the purpose of Formalin what are the advantages and disadvantages?
● An all-purpose fixative for the recovery of
protozoa and helminths.
● 5% concentration ideally preserves
protozoan cysts
● 10% concentration preserves helminth
eggs and larvae.
Advantages:
- It is easy to prepare
- It preserves specimens for up to several years
Disadvantages:
- It does not preserve parasite morphology
adequately for permanent smears - Trophozoites usually cannot be recovered
and morphologic details of cysts and eggs
may fade with time.
Describe the purpose of Polyvinyl Alcohol (PVA)
what are the advantages and disadvantages?
● Plastic powder that acts as an adhesive
for the stool specimen when preparing
slides for staining.
● PVA is most often combined with
Schaudinn solution, which usually
contains zinc sulfate, copper sulfate, or
mercuric chloride.
Advantage:
● The greatest advantage of this
preservative is that it can be used for the
preparation of a permanent stained smear.
Disadvantages:
● The biggest disadvantage of the use of
PVA is that the Schaudinn solution
contains mercuric chloride.
● The recovery of certain parasites is not as
effective as when formalin is used.
