Fa Flashcards
simplest and most frequently used
DFS
for the observation of the motility of trophozoites
0.85% NaCl
doesn’t demonstrate glycogen vacuole and nuclei
0.85% NaCl
cysts appear glistening and refractile
0.85% NaCl
for protozoan cysts and helminth ova
kill the trophozoites and helminth larva
D’antonis solution/Lugol’s Iodine
2 structures seen in cyst in D’antonis
Chromatodal bars and glycogen vacuole
Uses of coverslip
- to avoid drying of the preparation
- to avoid fogging and contamination of objectives
- to avoid rapid loss of the stain
Appropriate for formed or semiformed stool
Kts
For Emulsification of stool
Distilled water
Clearing agent in kts
Glycerin
Stain inkts
3% malachite green
Coverslip in kts
Cellophane
Clearing time of kts in room temp
1 hour
Clearing time of kts in dry incubation
20-30mins
Satisfactory for all kinds of helminth eggs
Kts
For large scale examination
Kts
Unsuitable for protozoan cysts and trophozoites
Kts
Detection of small number of parasites not detected using DFS
Concentration techniques
Protozoan cysts, helminth eggs and larvae
Sedimentation method
Less efficient than flotation: because protozoan cysts and
many eggs may not be seek.
Sedimentation method
Concentrate eggs, larvae and cysts of parasites, operculated and schistosomal eggs
Formalin-ether technique
Preservative and fixative
Formalin
How many minutes in formalin before centrifugation
Dissolves lipids and other colloidal material
Ether
Material can be examined hours or even days after preparation
FECT
Not applicable for protozoan cysts
Acid ether sedimentation
we may observe helminth eggs and larvae
Acid ether sedimentation
Cleraing agent in acid ether sedimentation
Not recommended because it is time consuming
Simple sedimentation
For blood only to detect microfilariae
Knott concentration technique
Helminths eggs and protozoan cysts may either float or sink depending on their specific gravitate
Flotation technique
Superior than sedimentation
Flotation method
Helminth eggs, protozoan cysts and larvae specific gravity
1.05-1.15
Chemical solutions specific gravity
1.12 to 1.21
Optimal time for examination of flotation method
5-20 minutes
Zinc sulfate centrifugal flotation technique specific gravity
1.18
80% effective in detecting eggs and cysts in light infections
ZINC SULFATE CENTRIFUGAL FLOTATION TECHNIQUE
Hookworm SG
1.005
Ascaris (fertile) sg
1.110
Trichuris sg
1.150
Giardia sg
1.060
E. Histolytica sg
1.070
Laboratory test for occult blood
Benzidine
Guiaic
Hematest
Meat free diet for how many days prior to occult blood test
3-5 days
False pos or false neg myoglobin in meat
False pos
False pos or false neg vitamin c
False neg
blood which is not visible to the naked eye and can only be detected by chemical means only
Occult blood
due to hemorrhagic disorder, ulcers and contamination
Rbc
PRESENT IN BACTERIAL OR PARASITIC INFECTION
Macrophages
indicative of inflammation
Wbc
Fungi in occult blood
Candida spp
Pseudoparasite in occult blood
Plant cells, pollen grains and spores
Increased during inflammation of the lower bowel
Epithelial cells
Contaminated by urine in occult blood
Calcium oxalate and triple phosphate crystls
Similar to helminth ova in occult blood
Plant fibers
Root hair
Animal cells
Mistaken by trichuris trichuria or karvae
Charcot latyden crystals
Color of glycogen vacuole
Mahigany brown
Uses specific gravity and centrifugation
Sedimentation method