General Stool Examination Overview

Study Notes

Collect 10-15 gm of stool in a dry, clean container, labeling it with the patient's name, date, and time of collection.
Send the sample to the laboratory as soon as possible.
Stool analysis is done for patients with abdominal pain, diarrhea, anemia, malnutrition, or abnormal stool color.

Consists of three parts: macroscopic (physical) examination, chemical analysis, and microscopic examination.

Examines the color, odor, consistency, and presence of parasites or blood in the stool.
Normal stool color is brown due to stercobilin and urobinin.
Abnormal colors include:
- Black: iron medication or upper GIT bleeding.
- Bright red: lower GIT bleeding.
- Pale brown: pancreatic deficiency.
- Yellow-green: rapid transit of feces through the intestines or lack of normal intestinal flora.
- Red brown: certain antibiotics.
Normal stool odor is mildly foul-smelling, but extremely foul-smelling stool can indicate malabsorption or infection.
Consistency of stool can be:
- Normal: well-formed.
- Abnormal: very hard (constipation), semi-formed (parasitic infection), soft (parasitic infection), loose (diarrhea), watery (bacterial infection).
Naked eye parasites can be seen in the stool, such as Ascaris lumbricoides and Entrobius vermicularis.

pH of stool is normally variable and diet-dependent, influenced by bacterial fermentation in the small intestine.
High alkaline stool can be caused by a high protein diet or colitis, while high acidic stool can be caused by a high carbohydrate diet or poor fat absorption.
Fat in stool can indicate malabsorption syndromes, such as coeliac disease, Crohn's disease, or pancreatic diseases.

Techniques used:
- Saline wet mount examination.
- Iodine examination.
Procedure for microscopic examination:
1. Place a drop of saline on a clean slide.
2. Add a small piece of stool and mix with saline, then cover with a cover slip.
3. Examine under 10X and 40X objectives.
4. Report the presence of:
  - Pus cells.
  - RBCs.
  - Amoebas, flagellates.
  - Eggs, larvae, and cysts.
Under the microscope, we can observe:
- Protozoa (e.g., Entamoeba histolytica, Entamoeba coli, Giardia lamblia).
- Worms (e.g., Enterobius vermicularis, Ascaris lumbricoides, Hookworm).
- Undigested food particles, indicating malabsorption or inadequate digestion.
- Mucus, indicating inflammation or irritation in the digestive tract.