Laboratory Safety and Specimen Collection, Handling and Disposal Flashcards
Potential Risks in the lab
- Ingestion of eggs/ova
- skin penetration of infective larva
- infection of non-parasitic agents
Keep the work areas ________
Basic Laboratory Rules
uncluttered
Always wash your hands with __________ when you enter and leave the laboratory.
Basic Laboratory Rules
soap and water
Always wear your laboratory coat when in the laboratory and remove it when leaving; laboratory coats and personal clothing should ______ in the same locker.
Basic Laboratory Rules
not be stored
Always wear _______ when handling potentially dangerous biological or chemical substances.
Basic Laboratory Rules
gloves
Are sandas allowed?
Basic Laboratory Rules
No
Wear ______ for protection against splashes, sprays and UV protection.
Basic Laboratory Rules
safety glasses
Handle toxic substances (e.g formalin) under a _____
Basic Laboratory Rules
safety hood
Unequivocally ____ all preparations and samples to be analyzed
Basic Laboratory Rules
label
Dispose of all ______ appropriately and safely
Basic Laboratory Rules
waste
_______ and _______ the work area at the beginning and end of each laboratory session
Basic Laboratory Rules
Clean
disinfect
________ of the laboratory clipboard/notepad/pen/pencil used for they are potentially contaminated
Basic Laboratory Rules
Do not take out
Do not store _______ in the laboratory
Basic Laboratory Rules
Food and Drinks
Do not eat and/or drink in the laboratory, nor bring hands or other objects (e.g. pencils, make-up, contact lenses) to your _________ or _______.
Basic Laboratory Rules
mouth or
eyes
Fixed stool specimens in _______ MAY STILL BE
INFECTIOUS
formalin
________ can still develop and are infectious even if preserved in formalin
Ascaris eggs
Timing: Blood should be collected _______ treatment is initiated
Specimen Collection, Handling and Disposal
before
________ exhibit periodicity
Specimen Collection, Handling and Disposal
Microfilariae
When ________ and ________ are suspected, blood smears should
be examined without delay
Specimen Collection, Handling and Disposal
Malaria and babesiosis
What type of blood sample is used?
Specimen Collection, Handling and Disposal
Venous blood or capillary blood
Fecal specimen is best collected in clean, wide-mouthed containers made of _________ or ________ with a tight-fitting lid to ensure retention of moisture and to prevent accidental spillage
Specimen Collection, Handling and Disposal
waxed cardboard or
plastic
Fecal specimen should be submitted with the following information:
Specimen Collection, Handling and Disposal
- patient’s name
- age
- sex
- date/time of collection
- requesting physician
- requested procedure
- presumptive diagnosis
- prior infections
- travel history
Intake of drugs/medicinal substances that can affect specimen:
▪ antacids
▪ anti-diarrheals
▪ barium
▪ bismuth
▪ Laxatives
This usually decreases the number of protozoans for several weeks
Intake of antibiotics
In routine stool examination, what size for formed stool?
thumb-sized specimen
Amount of stool to be collected dictated by the _________ that will be used
techniques
In routine stool examination, what size for watery stool?
5 to 6 tablespoons
Contamination with toilet water, urine, or soil must be prevented because it can destroy ________.
protozoan trophozoites
Contamination with toilet water, urine, or soil must be prevented because it may contain _______ that would complicate diagnosis of infections
free-living organisms
Age of the stool sample is very important for _________.
diarrheic specimens
trophozoites are likely to die within ________ after passage
30 minutes to 1 hour
Delay in examination of specimens
may require ________ to ensure that parasites are present in
the identifiable stage
preservation
What is the acceptable temperature in the temporary storage of fecal samples.
3-5°C
prolonged refrigeration can
bring about ________
desiccation
_________ are killed by refrigeration
trophozoites
What are usually not damaged in refrigeration?
helminth eggs and protozoan cysts
never freeze _______
stool samples
never keep stool samples in ______
incubators
an all-purpose fixative
Stool Preservatives
Formalin
Formalin concentration recommended for protozoan cysts
Stool Preservatives
5% concentration
Formalin concentration recommended for helminth eggs and larvae
Stool Preservatives
10% concentration
Formalin may be buffered with _________ to preserve the morphological characteristics of the organisms
Stool Preservatives
sodium phosphate
preserved stool can be concentrated using ________.
Stool Preservatives
formalin-ether/ethyl acetate concentration technique (FECT)
used to preserve fresh stool in preparation for staining the stool smears
Stool Preservatives
Schaudinn’s solution
Schaudinn’s solution contains __________ (highly toxic to humans; problems of mercury disposal may arise)
Stool Preservatives
mercuric chloride
a plastic resin which serves to adhere a stool sample onto a slide
Stool Preservatives
Polyvinyl alcohol (PVA)
Polyvinyl alcohol (PVA) is normally incorporated into the _________
Stool Preservatives
Schaudinn’s solution
(actual fixation is done by the Schaudinn’s)
main advantageof Polyvinyl alcohol (PVA): related to the preservation of protozoan cysts
and trophozoites for ________
Stool Preservatives
permanent staining
stools preserved in PVA can be concentrated using _______ and
can be shipped to any laboratory for further examination
Stool Preservatives
FECT
drawback of PVA: use of __________
Stool Preservatives
mercuric chloride
useful for the fixation of intestinal protozoans, helminth eggs,
and larvae
Stool Preservatives
Merthiolate-Iodine-Formalin (MIF)
Merthiolate-Iodine-Formalin (MIF) contains ___________ and _________ which
act as staining components
Stool Preservatives
merthiolate (also called thimerosal) and iodine
In Merthiolate-Iodine-Formalin (MIF), ______ acts as the preservative
Stool Preservatives
formalin
Merthiolate-Iodine-Formalin (MIF) is useful for the fixation of _________, ___________ and __________.
Stool Preservatives
intestinal protozoans, helminth eggs,
and larvae
has the advantage of not containing mercuric chloride
Stool Preservatives
Sodium acetate-acetic acid formalin (SAF)
Images of organisms fixed in SAF - after staining compared with those fixed in PVA or Schaudinn’s solution.
Stool Preservatives
not as sharp
a liquid fixative with a long shelf-life
Stool Preservatives
Sodium acetate-acetic acid formalin (SAF)
After processing fresh stool sample discard all used consumables (e.g. applicator sticks, slides) in a ___________.
container with bleach solution
After processing fresh stool sample, the remaining unprocessed fresh samples may be preserved or
discarded in a ________
yellow waste container
(stool must be tightly sealed inside the pilot container)
