PRL UNIT 1 Flashcards
Difference of Standard Precautions and Universal Precaution
Standard - everything is infectious
Universal - all samples are highly infectious
parasites that will be thriving in the host
Helminths
Type of Host during the adult stage
Definitive Host
Type of host during the larval stage
Intermediate Host
Type of Host during the Egg stage
Parasite in Diagnostic Stage
Types of Helminth
- Nematode
- Trematode
- Cestode
Potential risks in the laboratory
- Ingestion of eggs/ova
- Skin penetration of infective larva
- Infection of non-parasitic agents
Found in watery stool collect8ed and processed within 30 mins (or else parasites would die)
Trophozoite
T/F When a specimen is “fixed”, it means that everything is already killed. Hence, it is not infectious because you already preserved it.
True
T/F Fixed stool specimens in formalin may still be infectious
True
can still develop and are infectious because of its thick egg shell
Ascaris eggs
best way to preserve the eggs and prevent development
Warm / heated 10% Formalin
- Giant intestinal roundworm
- Larva is protected by a 3-layered membrane of protein
Ascaris Lumbricoides
important factor when blood specimen are collected
Timing
Blood smears should be examined without delay when this is expected
Malaria and Babesiosis
used to diagnose blood parasites
Blood
T/F Multiple blood smears might be needed
T
Reason why multiple blood smears are needed
Parasitemia or the presence of the parasites in the blood could actually flunctuate
exhibits periodicity and is seen in lymphatic fluids
Microfilariae
Time where the parasite is seen in the blood
Microfilariae
blood samples used in blood specimen to detect parasitic infection
Venous blood capillary or capillary blood samples
multiple specimens recommended for adequate yield of I parasite
Fecal specimen
Fecal specimen collection requirement
- Clean, wide-mouthed containers
- 0.5 pint (~240 mL)
- Waxed cardboard or plastic container
- Tight-fitting lid
- Sterile Container
reason why a container with a tight-fitting lid is used for fecal collection
to ensure retention of moisture and to prevent accidental spillage
Specimen Protocol
__ specimen/s collected every other day to consider adequate/min necessary for detection of O&P (w/ no more than __ days)
3 specimens, 7 days
Specimen Protocol
__ specimen/s for the diagnosis of intestinal amebiasis (w/ no more than __ days)
<6 specimens, 10 days
Proper stool collection
- Do not let stool touch toilet water as it can lead to contamination
- Do not defecate on the container directly
Fecal specimen patient information in container
- Patient name and ID number
- Requesting physician
- Date & Time of Collection`
Required information if fecal specimens
- Patient Name
- ID number
- Age
- Sex
- Date/Time of Collection
Fecal specimen should be submitted with the following patient information
- Patient’s name
- Age
- Sex
- Date/Time of collection
- Requesting Physician
- Requested Procedure
- Presumptive Diagnosis
- Prior Infections
- Travel History
date and time of collection
- Liquid stool
- Semi-formed stool
- Formed stool
- Liquid stool - 30 mins
- Semi-formed stool - an hour
- Formed stool - up to 24 hrs
__________ should be found on the label of the container, whereas the remaining information is found on the requisition form
Patient’s name, age, sex and date/time of collection
Important Factors to consider
- Intake of drugs / medicinal substances
- Intake of antibiotics
- Amount of stool to be collected
- Contamination with toilet water, urine, or soil must be prevented
- Age of the stool sample is very important for diarrheic specimens
- Delay in examination of specimens
- Temporary storage of fecal samples
Cause of Intake of drugs / medicinal substances to fecal specimen
can form a crystalline residue which can interfere with the parasite identification
Deferral for Intake of Drugs
1 week after last intake
Cause of Intake of antibiotics
decreases the number of protozoans for several weeks; may eliminate the parasite causing a false negative result
Deferral for Anti-protozoan drugs
3-4 weeks after intake
Deferral for Anti-helminthic drugs
5-6 weeks after intake
Stool sample that contains protozoan cyst
Formed stool
Stool sample that contains trophozoites and must be tested within 30 minutes mark
Watery stool
Amount of stool collected
- Formed stool
- Watery stool
Amount of stool collected
- Formed stool - thumb-sized specimen
- Watery stool - about 5-6 tablespoons
Cause of contamination with toilet water, urine, or soil to specimen
- Can destroy protozoan trophozoites
- May contain free-living organisms that would complicate diagnosis of infectious disease
T/F Age of the stool sample is very important for diarrheic specimens
T
Cause of delay in examination of specimens
parasites present may not be identifiable when delayed
acceptable temp for refrigeration
3-5 C
cause of prolonged refrigeration to specimen
Dessication
Cause of Refrigeration to :
- Trophozoites
- Helminth eggs
- Protozoan cysts
- Killed
- Usually not damaged
- Usually not damaged
Type of refrigerator used to stool fecal specimens
Dirty Ref
2 rules in temporary storage of fecal samples
- Never freeze stool samples
- Never keep them in incubators
Stool Preservatives
- Formalin
- Schaudinn’s Solution
- Polyvinyl Alcohol PVA
- Merthiolate-Iodine-Formalin (MIF)
- Sodium acetate-acetic acid formalin SAF
An all-purpose fixative for the recovery of protozoans & helminth
Formalin
Formalin fixative ratio
1:3
Difference of formalin w :
- 5% concentration
- 10% concentration
- 5% concentration - for protozoan cysts
- 10% concentration - for helminth eggs and larvae
used to preserve fresh stool specimens or sample from the intestinal mucosal surface for permanent staining
Schaudinn’s Solution
Best to preserve the parasite
Schaudinn’s Solution
Partner for schaudinn’s solution and acts as an adhesive to ensure that stool sample is attached
Polyvinyl Alcohol PVA
Can be a substitute for the schaudinn’s solution and useful for fixation of intestinal protozoans, helminth eggs, and larvae
Merthiolate-Iodine-Formalin (MIF)
A liquid fixative with a long shelf-life; used in concentration techniques but does not contain mercuric chloride
Sodium acetate-acetic acid formalin SAF
Remaining unprocessed fresh samples may be preserved or discarded in a ____
yellow waste container
Applicator stick from the fecal diagnostics and blood specimens will be submerged in _____
10% or 1: 10 hypochlorite solution
Advantage and Disadvantage of :
Formalin
A : for stool concentration; long shelf-life
D : Cannot preserve the protozoans trophozoite completely; not adequately preserve morphology
Advantage and Disadvantage of :
Schaudinn’s Solution
A : preserve
the morphology of the protozoans cyst and trophozoites; used for permanent staining
D : contains mercuric chloride
Advantage and Disadvantage of :
MIF
A: Easy to prepare, long shelf life, useful for field surveys
D : Inadequate preservation of morphology of trophozoites
Advantage and Disadvantage of :
SAF
A : Has the advantage of not containing mercuric chloride; long shelf-life
D : images of organisms fixed in SAF are not as sharp after staining
Advantage and Disadvantage of :
PVA
A : Related to the preservation of
protozoan cysts and trophozoites for permanent staining
D : Use of mercuric chloride
The percentage of Formalin recommended for helminth eggs and larvae.
10%
Blood specimens for parasite detection should be collected before treatment is initiated True or False)
True
A plastic resin which serves to adhere a stool sample onto a slide.
Polyvinyl Alcohol PVA
A stool preservative with mercuric chloride.
Schaudinn’s Solution and Polyvinyl Alcohol PVA
It may be buffered with sodium phosphate to preserve the morphological characteristics of the organisms.
Formalin
What is the recommended amount of specimen when testing formed stool
Thumb-size
What is the recommended amount of specimen when testing watery stool?
~ 5- 6 tablespoons
The Lugol’s iodine component should always be freshly prepared since it is unstable.
True
Formalin 10%concentration) is recommended to preserve protozoan cysts.
False
Freezingstoolsamplesfor routine fecalysis is acceptable.
False
Stool contaminated with toilet water must be rejected for analysis.
True
Keeping stool samples in the incubator enhances recovery of protozoan cysts.
False