General Stool Examination Overview

General Stool Examination (GSE)

• 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.

Stool Analysis Basics

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

Macroscopic (Physical) 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.

Chemical Analysis

• 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.

Microscopic Examination

• 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.

A test on a stool sample to diagnose conditions affecting the digestive tract. Learn about the collection of fecal specimens and more.