PARA LAB Flashcards
Among the specimens available for parasitic
examinations, the ______ is most commonly
utilized
stool
Stool samples should
be collected a ________ after the last intake of any drugs.
week
drugs that leave
crystalline residues
- antacids
- anti-diarrheals
- barium
- bismuth
- laxatives
A routine stool examination
usually requires a ___________
specimen of formed stool or about __________________ of watery stool.
thumb-sized, 5 to 6 tablespoons
Temporary storage of fecal samples in a refrigerator with temperature at around ______ is acceptable, but prolonged refrigeration can bring
about ____________
(3-5°C), desiccation
is an all purpose fixative
Formalin
A ____ concentration formalin is recommended for protozoan cysts, while a ______ concentration formalin is recommended
for helminth eggs and larvae
5%, 10%
The formalin solution may be buffered with _______________ to preserve the
morphological characteristics of the organisms.
sodium phosphate
is used to
preserve fresh stool in preparation for
staining the stool smears.
Schaudinn’s solution
Schaudinn’s solution contains
______________ which is highly
toxic to humans.
mercuric chloride
is a plastic resin which serves to adhere a stool sample onto a slide
Polyvinyl alcohol (PVA)
Polyvinyl alcohol (PVA) is normally
incorporated into the _________________, therefore the actual fixation is done by this fixative
Schaudinn’s solution
One major drawback of
PVA is the use of mercuric chloride. Some laboratory technologists have suggested replacing this compound
with ______________________
cupric sulfate.
It is useful for
the fixation of intestinal protozoans,
helminth eggs, and larvae
Merthiolate-iodine-formalin (MIF)
Merthiolate-iodine-formalin (MIF)
contains merthiolate (also called
thimerosal) and iodine which act as __________________, while formalin acts as the ___________________
staining components, preservative
has the advantage of not
containing mercuric chloride, however, are
not as sharp after staining compared
with those fixed in PVA or Schaudinn’s
solution.
Sodium acetate-acetic acid formalin (SAF)
It is a liquid fixative with a
long shelf-life.
Sodium acetate-acetic acid formalin (SAF)
__________________ are generally observed
in soft or liquid stool,
Protozoan trophozoites
______________________ are often
found in formed or semi-formed samples.
Protozoan cysts
____________________________ can be found in any type of consistency.
helminth eggs and
larvae
_______________________
suggests bleeding high up in the gastrointestinal
tract, while _________________ means bleeding
from a more distal location
Dark-colored blood, bright red blood
_________________________
in soft or watery stools may possibly yield the
presence of trophozoites
Blood and mucus
can reveal many
elements present in the intestinal tract aside
from parasites and normal fecal constituents
Microscopic examination
Presence of ______________________ in stool may indicate inflammation
Polymorphonuclears (PMNs)
Presence of ______________________ in stool may indicate
an immune response to a parasitic
infection
Eosinophils
Presence of ______________________ in stool may indicate
ulcerations or bleeding
Red blood cells
are released
with the disintegration of eosinophils.
Charcot-Leyden crystals
Presence of ______________________ may indicate presence of
hypersensitivity or parasitic infections,
especially amebiasis.
Charcot-Leyden crystals
This is a routine method of stool
examination primarily useful in the detection
of motile protozoan trophozoites.
Direct Fecal Smear (DFS)
in Direct Fecal Smear (DFS) About __________ of stool is
comminuted thoroughly with a drop of _____________________ and then covered with a cover slip
2 mg, 0.85% sodium chloride solution (NSS)
Trophozoites can be stained
to demonstrate the nuclear morphology using
______________________ solution.
Nair’s buffered methylene blue (BMB)
_________________ cytoplasm will stain pale blue and the nucleus, darker blue.
Entamoeba
a tool to measure cysts
and ova, will be useful in specific species
identification
Micrometry
The technique is simple and economical, and is therefore useful in mass stool examinations.
It is very good in detecting eggs with thick shells
(e.g., Ascaris and Trichuris) but not eggs with
thin shells (e.g., hookworm).
Kato Thick Smear
in Kato Thick Smear About ____________________ of stool is placed over a glass slide and covered with cut cellophane paper
soaked in a mixture of ____________________
50 to 60 mg, glycerine and malachite green solution
____________ is a clearing solution
and _______________ is used to give color to the cellophane in order to give a pale green background to the eggs and to minimize the
brightness of the microscopic field.
Glycerine, malachite green
Kato Thick Smear preparation is best examined within _________________
10 to 20 minutes.
can separate
protozoan cysts and helminth eggs from a
larger amount of stool (usually 1 g in amount)
based on differences in specific gravity
Concentration Techniques
In cases of light infections, or if there is a need to recover more parasites, ____________________
procedures are recommended
stool concentration
a technique where the parasite that has a higher specific gravity than the reagent will sink to the bottom of the preparation,
while a parasite with a lower specific gravity will float to the surface
sedimentation techniques
This technique is recommended for the recovery of Trichuris, Capillaria, and trematode eggs,
especially Schistosoma.
Acid Ether Concentration Technique (AECT)
This is the choice if
stool material comes from animals like cats and
dogs.
Acid Ether Concentration Technique (AECT)
Drawbacks in the use of this technique
include: loss of parasite to the plug of debris and
possible destruction of protozoan cysts
Acid Ether Concentration Technique (AECT)
The one of the main reagents of AECT which can dissolve albuminous material
40% HCl
The one of the main reagents of AECT which can dissolve neutral fats in the stool.
Ether
This technique is useful in the recovery of both helminth eggs and protozoan cysts
Formalin-Ether/Ethyl Acetate Concentration Technique (FECT)
The one of the main reagents of FECT is an all purpose fixative
10% formalin
The one of the main reagents of FECT which can dissolve neutral fats in the stool.
Ether
________ can be done with
formalin-preserved and PVA-preserved stools.
FECT
Sediments from _____ can be stored for a long
period of time.
FECT
If parasites are exposed to
high specific gravity, distortion and shrinkage
of ________ and _________________ may occur.
protozoan cysts, thin-walled nematode eggs
two types of sedimentation procedures:
> Acid ether concentration technique
> Formalin-ether/ ethyl acetate concentration technique
The ideal specific gravity ranges
from ______________
1.18 to 1.20
The main reagent is a 33% zinc sulfate solution
Zinc Sulfate (ZnSO4) Flotation
This makes use of a saturated table salt solution. Stools are directly mixed with the brine solution.
Brine Flotation
This flotation technique is low-cost and simple but helminth eggs like hookworm and
Schistosoma become badly shrunken
Brine Flotation
in Brine Flotation There is no need for centrifugation since ____________ rise to the surface of
the solution.
helminth eggs
Brine Flotation is not useful for ____________ like Clonorchis,
Opistorchis, and heterophyids because these do not float in brine solution
operculated eggs
This technique is
considered the best for the recovery of coccidian
oocysts, mainly Cryptosporidium, Cyclospora, and
Cystoisospora.
Sheather’s Sugar Flotation
Positive stools are mixed with moistened soil or granulated charcoal. This simulates environmental conditions in nature.
Copro Culture
Copro Culture Larvae
are harvested using the _________________________
Baermann procedure.
This technique makes use of test tubes and filter paper strips.
Harada-Mori or the Test Tube Culture Method
in Harada-Mori or the Test Tube Culture Method, ____________________ will generally move downwards against the upward capillary movement of water and can therefore be recovered from the water
at the bottom of the tube
Filariform larvae
in Harada-Mori or the Test Tube Culture Method, ___________________ may instead move upwards and accumulate at the upper end of the filter paper strip
Strongyloides larvae
may help correlate
the severity of clinical disease with the intensity
of infection or worm burden
Egg counting procedures
It is done to assess the efficacy of anthelminthics and the reduction of worm burden following
treatment
Egg Counting Procedures
This procedure uses a measured amount of stool which has been sieved through a wire mesh
and pressed under cellophane paper soaked in glycerine-malachite green solution
Kato-Katz Method or the Cellophane Covered Thick Smear
The procedure is useful for assessing the
intensity of infection with Schistosoma and
common soil-transmitted helminths like Ascaris,
Trichuris, and hookworm
Kato-Katz Method or the Cellophane Covered Thick Smear
2 types of Stool Culture Method
> Copro culture
Harada-Mori or the Test Tube Culture Method
3 types of Flotation Procedures
> Zinc Sulfate (ZnSO4) Flotation
Brine Flotation
Sheather’s Sugar Flotation
2 types of Egg Counting Procedures
> Kato-Katz Method or the Cellophane Covered Thick Smear
Stoll Egg Count
This technique makes use of 0.1 N NaOH and a stool displacement flask calibrated at 56
mL and 60 mL
Stoll Egg Count
Kato-Katz Method can only be
done on _____________________
fresh formed stools
done specifically in the examination of the nuclear
characteristics of amebae
Staining of stool specimen
useful in the identification of the other intestinal
protozoans like Balantidium and Giardia
Staining of stool specimen
Staining of stool specimen Techniques available include:
- Iron-Hematoxylin
- Trichrome
- Periodic Acid Schiff (PAS)
- Chlorazol Black E
can be used to recover
eggs of Enterobius vermicularis and Taenia spp.
Perianal Swab
This is done by sampling the perianal skin
using a strip of cellulose tape attached onto
a glass slide
Cellulose Tape or Scotch Tape Method
