General Stool Examination (GSE)

General Stool Examination
(GSE)
Stool is waste material excreted from the intestine. Normal stool consist of :
• Undigested food.
• Intestinal secretions e.g. enzymes and mucin.
• Intestinal flora (non pathogenic bacteria) and their products.

Collection of samples
• A wide mouth jar with a screw cap is good enough.
• A clean dry container must be used without any foreign materials. Urine and water will destroy trophozoites, if present, and the presence of dirt also causes identification problems.
• Never be over filled and should be opened slowly to release the gas.
Visual observation of the faecal sample
• Normal stool is soft & brown color.
• pH of stools is acidic in amoebic dysentery and is alkaline in bacillary dysentery.

Macroscopic finding:
• color
• form (consistency, appearance)
• blood
• mucus

Types of stool

Type of stool Likely reason
Watery Diarrhea
Large amount of mushy, foul smelling, gray stool that flout in water. Steatorrhoea.
Clay colored Obstructive jaundice or presence of barium sulfate
Reddish colored Blood from lower gastrointestinal tract, beef consumption.
Black Bleeding from upper gastrointestinal tract, Iron, charcoal.
green Ingestion of Spinach, antibiotics.
Procedure for the microscopic examination of faecal samples for parasites
1. Place a drop of saline on a clean slide.
2. Place a small piece of stool on the slide and mix with saline, cover with a cover slip. If the specimen contains mucus, the examination prefers to be done without saline. The mucus is put on the slide and covered with cover slip.
3. Examine under 10X and 40X objectives.
4. report the presence of :
• Large numbers of pus cells
• RBCs
• Amoebas, flagellates
• Eggs, larvae & cysts and yeast.
Using of Saline: Normal saline (0.85%) is used for routine examination of stool samples, as it is isotonic.
Using of Iodine: Iodine is used to examine the nuclei of cysts.
Using of Eosin 1%: this provides a pink background and that will help to clear the unstained objects.
Occult blood: Occult blood may be present in a number of diseases
including malignancy of the gastrointestinal tract. The reagent used is
benzidine powder. A pinch of benzidine powder is taken in a test tube and
acidified with 1-2 drops of glacial acetic acid and is mixed well in it. To
this is added 1ml of hydrogen peroxide which is again mixed well. Then
place a clean glass slide and place a small quantity of stool on it. Place
1-2 drops of the benzidine mixture prepared earlier on the stool specimen
taken on the glass slide and observe for a change of colour. Development
of green to blue colour is indicative of presence of occult blood in the stool
specimen.
















Entamoeba histolitica










Giardia lamblia









Enterobius vermicularis (Pin worm)









Ascaris lumbricoides










Hook worm




Taenia saginata






Fasciola hepatica







Schistosoma japanicum




Schistosoma mansoni