1. Stool analysis: A stool analysis is a series of tests done on a stool (feces) sample for differential diagnosis of certain diseases of digestive system. Stool analysis procedure is divided into: 1-Physical Examination. 2-Chemical Examination. 3-Microscopic Examination.

2. Clinical significance of stool analysis: 1-Diagnosis of digestive system infectious diseases: Bacteria, parasites, virus, and fungi. 2-Diagnosis of pancreas disorders (inflammation); which associated with malabsorption of nutrients. 3-Primary screening test for some types of digestive system malignancy such as: Colon cancer. 4-Primary screening test for peptic ulcer disease, and some types of anemia.

3. For whom Stool analysis is urgently required? 1-Patients with abdominal pain. 2-Patients with diarrhea. 3-Patients with anemia. Other situations by which Stool analysis is non-urgently required: 1-Patients who is too thin or do not grow well. 2-Patient with stool color that is changed to abnormal color.

4. Stool analysis: 1-Physical Examination: A-Color: Normal feces has a dark brown color. (Bilirubin in the presence of bacteria will be oxidized to urobilinogen which give stool its color). Abnormal color: 1- Black color indicates blood of upper GIT origin. 2- Red color indicates blood of lower GIT origin. 3- White color indicates yeast fermentation (Candida). -Very pale color indicates biliary obstruction or barium enema.

5. N Physical Examination: B-Consistency: -Normal feces is solid to semi-solid depending on diet. -A ribbon like fecal specimen could indicate irritable bowl syndrome or GIT obstruction. -Liquid stool indicates diarrhea (Gastroenteritis). -Fatty stool indicates mal-digestion ; Vitamins deficiency. (A,D,E,K Group).

6. Chemical Examination: 1-The pH: The pH of the stool is 7.0-7.5. 2-Suger contents: The stool contains less than 0.25 grams per deciliter (g/dL) or less than 13.9 millimoles per liter (mmol/L) of sugars. -Elevated Suger indicates (more than 0.5g/dl): -Lactose intolerance. 3-Fat contents: The stool contains 2-7 grams of fat per 24 hours (g/24h). Steatorrhea: 95% ethanolic-Sudan black-II stain or Acetic acid: 60 red droplets of neutral fats on HPF.

7. N -High levels of fat in the stool may be caused by diseases such as pancreatitis, celiac disease,or cystic fibrosis. -Celiac disease (allergy to Gluten protein in wheat). 4-Occult blood: (The stool guaiac test): -Occult blood can be detected chemically : 1- Paper surface with phenolic compound alpha-guaiaconic acid. 2- Stool applied to the paper. 3-Hydrogen peroxide oxidizes alpha-guaiaconic acid to dark- blue color within two seconds. 4-Heme is a catalyst of this reaction.

8. N Patients should be instructed to avoid red meat, horse- radish, Aspirin, Vitamin C as they interfere with the test by their catalases and peroxidases. Clinical significance of the test: 1-Diagnosis of Colorectal cancer. 2-Diagnosis of ulcer hemorrhoids. 3-Invasive Gastroenteritis.

9. Stool analysis form: N

10. Microscopic Examination: -Fecal leukocytes, especially neutrophils are associated with dysentery. -They can be detected by dried smears of the stool stained with gram stain. -Wet-mount smear(0.9% Saline) or Iodine stained smear should be prepared for parasites identification. 1-Wet-mount smear : Show the motility of active Protozoa. 2-Iodine smear: Show the nucleus and karyosome of protozoa.

11. Amoebic dysentery: Entamoeba histolytica (Rhizopoda): -Offensive stool. -Faecal matter mixed with blood and mucus. -RBCs, pus, mucus, and Entamoeba histolytica cyst or/and trophozoite (central karyosome). -Trophozoite show motility in one direction.

12. Entamoeba histolytica life cycle: N

13. Giardia intestinalis : -Gastrointestinal Mastigophora. -Habitat: Small intestine especially in duodenum. -Disease: Fatty diarrhea especially in children. -Morphology: Trophozoite: four pairs of flagella. Giardia cyst (infective and diagnostic) Giardia trophozoite (diagnostic stage).

14. Balantidial dysentery: Balantidium coli: -Ciliophora. -Kidney-shaped Macronucleus. -Small micronucleus. -Ingestion of Contaminated pork meat.

15. Helminthes: Schistosoma mansoni: -Trematoda. -Intestinal bilharziasis. -Diagnosis: finding of ova in stool. Ova with Lateral spine (diagnostic stage)

16. Cysticercosis: Taenia (Cestoda) infection: 1- Taenia saginata (beef tapeworm). 2- Taenia solium (pork tapeworm). Diagnostic stages: 1-Gravid segments. 2-Hexacantho- embryonated ova.

17. Ascaris lumbricoides life cycle: N

18. N Ascaris lumbricoides: -Nematoda. -Diagnostic stage: 1-Fertilized, un-fertilized ova. 2-Embryonated ova. 3-Adult stage.

19. N Hook worms: -Ancylostoma duodenale. -Nematoda. -Diagnostic stage: 4-8 cell stage Embryonated ova.

20. N Enterobius vermicularis: -Nematoda. -Diagnostic stage: D-shaped ova. D-Shaped Ova.

21. N Strongyloides stercoralis: -Free-living Nematoda. -Diagnostic stage: Rhabditiform larvae in stool.

22. n Trichocephalus trichiuris adult: barrel shaped-egg with two polar plugs