Podcast
Questions and Answers
What is the purpose of concentrating feces in a laboratory setting?
What is the purpose of concentrating feces in a laboratory setting?
Before conducting fecal concentration techniques, what should be done first?
Before conducting fecal concentration techniques, what should be done first?
What does the sedimentation technique rely on to separate parasites from the sample?
What does the sedimentation technique rely on to separate parasites from the sample?
Why are motile protozoan trophozoites not found in concentrated preparations?
Why are motile protozoan trophozoites not found in concentrated preparations?
Signup and view all the answers
Which concentration technique is recommended for the recovery of Trichuris, Capillaria & Schistosoma eggs from animal specimens?
Which concentration technique is recommended for the recovery of Trichuris, Capillaria & Schistosoma eggs from animal specimens?
Signup and view all the answers
What is the clearing agent used in the formalin ethyl acetate concentration technique?
What is the clearing agent used in the formalin ethyl acetate concentration technique?
Signup and view all the answers
What is the advantage of using ethyl acetate in the centrifugation technique described?
What is the advantage of using ethyl acetate in the centrifugation technique described?
Signup and view all the answers
What is the main disadvantage of using the zinc sulfate centrifugal flotation technique?
What is the main disadvantage of using the zinc sulfate centrifugal flotation technique?
Signup and view all the answers
Why is Sheather's flotation technique recommended for concentrating Cryptosporidium oocysts?
Why is Sheather's flotation technique recommended for concentrating Cryptosporidium oocysts?
Signup and view all the answers
Why is Brine's flotation not suited for recovering Trematode eggs?
Why is Brine's flotation not suited for recovering Trematode eggs?
Signup and view all the answers
What is the main benefit of using zinc sulfate centrifugal flotation over ethyl acetate technique?
What is the main benefit of using zinc sulfate centrifugal flotation over ethyl acetate technique?
Signup and view all the answers
Why would hookworm eggs and Schistosome eggs be badly shrunken in Brine's flotation?
Why would hookworm eggs and Schistosome eggs be badly shrunken in Brine's flotation?
Signup and view all the answers
Study Notes
Purpose of Concentrating Feces
- Increase the possibility of finding protozoan cysts, helminth eggs, and larvae by decreasing background material and concentrating organisms.
Importance of Direct Examination
- Should be done before proceeding to fecal concentration, especially for light infections.
Concentration Techniques
- Can be performed on fresh or preserved stool specimens.
- Increase the number of organisms detected compared to direct microscopy.
- Motile protozoan trophozoites are not found in concentrated preparations.
Sedimentation Technique
- Based on principle of specific gravity: parasites settle at the bottom of the tube after centrifugation.
Flotation Techniques
- Parasites float to the surface and can be skimmed from the top of the tube.
Acid Ether Concentration Technique
- Method of choice for specimens from animal sources.
- Recommended for recovering Trichuris, Capillaria, and Schistosoma eggs.
- Uses HCl as a clearing agent and ether to remove fats.
Formalin Ethyl Acetate Technique
- Most widely used sedimentation technique.
- Recommended for recovering Giardia lamblia cysts and cestode eggs.
- Provides good recovery of most parasites and is easy to perform.
Zinc Sulfate Centrifugal Flotation Technique
- Uses zinc sulfate with a specific gravity of 1.18 to 1.20 as the concentrating solution.
- Recommended for recovering Giardia lamblia cysts and H. nana ova.
- Advantage: removes more fecal debris, yielding a cleaner preparation.
- Disadvantage: may miss some helminth eggs due to density.
Sheather's Flotation Technique
- Uses sugar solution preserved in phenol.
- Recommended for concentrating oocysts of Cryptosporidium and Isospora.
Brine's Flotation Technique
- Uses salt solution, with no centrifugation required.
- Procedure is simple, economical, and suited for mass stool examination.
- Not recommended for Trematode eggs as they do not float in brine.
- Hookworm eggs and Schistosome eggs become badly shrunken.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on fecal concentration techniques used to find protozoan cysts, helminth eggs, and larvae in medical samples. Learn about the importance of concentrating feces and how it increases the chances of detecting organisms compared to direct examination.
