Laboratory: Examination of Parasites in Blood Specimen Flashcards
Capillary blood should be free-flowing and not contaminated with the alcohol used to cleanse the puncture site. True or False?
True
Anticoagulants do not cause distortion to the staining process and subsequent. True or False?
False, it does cause some distortion.
If malaria is suspected, it is best to prepare smears within _ hour of collection
1 hour
Methods of Blood Examination for Venous Blood Sample
Knott’s Concentration Method
Membrane Filtration Method
Methods of Blood Examination for Finger-Prick Blood Sample
Wet/Fresh Preparation
Capillary Tube Method
Stained Smears
This method is designed to concentrate blood specimens suspected of containing low numbers of microfilariae
Knott’s Concentration Method
Supernatant is discarded and sediment is smeared and stained with Wright stain in Knott’s Concentration Method. True or False?
False, it is stained with Giemsa
How many mL of blood is needed in Membrane Filtration Method?
1 mL
How many mL of distilled water is added in Membrane Filtration Method?
10 mL
What is the filter used where the combined blood and distilled water pass through?
Swinney filter
What stain is used in Membrane Filtration Method?
Dilute Giemsa
Types of membrane filters used for MFM?
Millipore
Nucleopore
What is the most sensitive method?
Membrane Filtration Method
Species identification is not possible in what method?
Wet or Fresh Preparation
In Buffy Coat Film, what is the color of the nuclear material and cytoplasm of L. donovani?
Dark red-purple
Light blue
What can be detected in large mononuclear cells found in buffy coat?
L. donovani
Trypanosomes
Histoplasma capsulatum
What is the pre-coating of capillary tube in QBC?
Acridine orange
Potassium oxalate
What can be found in buffy coat?
Lymphocytes
Monocytes
Granulocytes
Platelets
This is the stain of choice because it provides optimal detail of intracellular malarial parasites
Giemsa stain
This stain already contains alcohol so fixation is not required before staining
Wright’s stain
This stain is used to improve visibility of the microfilarial sheath
Delafield’s Hematoxylin stain
Percentage of formalin and acetic acid that dehemoglobinize thick films?
2% formalin
1% acetic acid
If whole blood is used: examiner should continue stirring about _ seconds to prevent the formation of fibrin strands
30 seconds
Are thick films used for screening purposes? True or False?
True
This smear is used routinely used for parasite identification to the species level
Thin Films/Smear
Name of method done using two clean glass slides to produce thick on one end and thin and feathery at the other end
Wedge method
Push slide technique
Condition of blood where the morphology of both parasites and infected RBCs may not be typical
Anticoagulated blood from an hour ago
Which is examined first, thin smear or thick smear?
Thin smear
pH level of buffer used in Giemsa staining
pH 7.0-7.2
Ratio of Giemsa to buffer
1 part Giemsa stock : 10-50 parts buffer
Lack of _ fixation allows for lysis of red cells in the Giemsa staining solution.
Methanol
How many fields before a film is reported as negative?
100-300 fields
Preferred is 100, only 300 for non-immune patients
If 200 leukocytes were counted; no. of parasites counted is multiplied by?
40
if 500 leukocytes were counted; no. of parasites counted is multiplied by?
16
Color of Leishmania, trypanosome, malaria and Babesia nuclear structures when stained
Red
Color of cytoplasm when stained
Blue
Color of Schiffer’s dot when stained
Red
Color of nuclei when stained
Blue to purple
Color of sheath when stained
Clear, may not stain
Color of RBC when stained
Pale red
Color of WBC when stained
Purple
Color of neutrophilic granules when stained
Pink-purple
Color of eosinophilic granules when stained
Purple-red
Smear used for screening parasites, detecting mixed infections
Thick Film/Smears
