Laboratory: Preparation for Fecal Smear Flashcards
Nuclei of epithelial cells and macrophages can be seen in
BMB (Buffered methylene blue)
Methods in Preparation
Direct Fecal Smear
D’ Antoni’s Method
Kato Thick Smear
Kato-Katz Smear
The direct wet mount is performed to detect motile
protozoan trophozoites and to determine cellular morphology
Direct Fecal Smear
Percentage of NaCl Solution when NSS is not available
0.85%
The most common temporary stains are
Dilute iodine
MIF solution
BMB solution
Most useful for recognition of cyst stages. Their morphologic appearance is enhanced clearly with the addition of iodine solution which acts as the stain
D’ Antoni’s Method
D’ Antoni’s reagent
Potassium iodide – 1.0g
Iodine crystals – 1.5g
Distilled water – 100mL
Year when Kato and Miura first introduced a new method, the “cellophane thick smear technique”
1954
Useful for helminth eggs with thick shells such as Ascaris and Trichuris but not for helminth and larvae or protozoa
Kato Thick Smear
Size of Pre-heated/Hydrophilic cellophane
25x30mm or 25x35mm
Cellophanes are soaked in
Glycerol-malachite green solution
Glycerol-Methylene blue solution
Components of Glycerol-Malachite Green and Glycerol-Methylene Blue
Glycerol/Glycerin/Glycerine – 100mL
3% Malachite Green / 3% Methylene blue solution –
1mL
Distilled water – 100mL
How long should it be before slides causes drying and shells of hookworm will dissolve in glycerin solution?
Greater than 1 hour
Useful for assessing the intensity of infection in schistosomiasis and common soil-transmitted helminthiasis like ascariasis,
trichuriasis and hookworm infection
Kato-Katz Tehchnique
Consistency of the stool is the main determinant for the
sensitivity of Kato-Katz technique
Specific for fresh, formed and preferably drier stool samples
Schistosoma spp. may be recognizable for up to _, it is best observed within _
Several months
24 hours
Hookworm eggs clear rapidly and will no longer visible after
30-60 minutes
Wire net specifications
105 mesh or layer of gauze
1mm thick template with a 9mm hole
50mg of feces
1.5mm thick template with a 6mm hole
41.7mg of feces
0.5mm thick template with a 6.5mm hole
20mg feces
EPG of template with a 9mm hole
Number of eggs counted x 20
EPG of template with a 6mm hole
Number of eggs counted x 24
EPG of template with 6.5mm hole
Number of eggs counted x 50
Formula of no. of eggs of parasite per grams of feces
No. of eggs of parasite counted over No. of mg of feces multiplied by 1000 mg/g
When amoebic cysts are stained with iodine
Glycogen = dark - red-brown color
Cytoplasm = yellow color
