Stool Test PDF

Collage of Science Al-Qadisiya University Dept. Pathological analysis GENERAL STOOL EXAMINATION G.S.E 1stage / 2nd course La...

Collage of Science Al-Qadisiya University Dept. Pathological analysis GENERAL STOOL EXAMINATION G.S.E 1stage / 2nd course Lab. (2) Asst. lect. Shahad Ali Mahdi  General Stool Examination stool analysis is a test on a stool (feces) sample to help diagnose certain conditions affecting the digestive tract. Collection of Fecal Specimens: Collect about 10-15 gm the stool in a dry, clean, container. Make sure no urine, water, soil or other material gets in the container. Label the specimen with the patient’s name, date and time of collection and send it with a request form to reach laboratory as soon as possible. Fresh stool should be examined immediately, or preserved.  Stool analysis may be done for these patients 1. Patient with abdominal pain or abdominal discomfort 2. Patient with diarrhoea 3. Patient with anaemia 4. Patient who is too thin or do not grow well 5. Patient with stool colour that is changed to abnormal colour  Stool analysis Basics Stool analysis consists of the following: Macroscopic (Physical) Examination Chemical Analysis Microscopic Examination Macroscopic (Physical) Examination 1- The color of stool 2- Odor 3- Consistency of stool 4- Naked eye parasite 5- Gross blood 6- Mucus 1- The color of stool Normal color of stool is brown. The characteristic brown color of feces is due to stercobilin and urobinin, both of which are produced by bacterial degradation of bilirubin. Abnormal color: Black color: indicate iron medication (for treatment of anemia ) or upper GIT bleeding (due to peptic ulcer or stomach carcinoma). Bright red color (Hematochezia): indicate lower GIT bleeding (due to anal fissure). Pale brown color: with a greasy consistency indicate pancreatic deficiency causing malabsorption of fat (often with offensive odor). Yellow-green color: occurs in the stool of breast-fed infants who lack normal intestinal flora (low bile conversion) and may also occurs due to rapid transit of feces through the intestines. Red brown color: indicate drugs as Tetracyclines, and Rifambicin antibiotics 2- Odor Fecal odor is normal to some extent, but extremely foul-smelling stool can be a sign of malabsorption or an infection 3- Consistency of stool Normally well formed Abnormal: Very hard: seen in cases of constipation Semi formed: seen in the cases of parasitic infection Soft: seen in the cases of parasitic infection Loose: seen in the cases of diarrhea Watery: mostly seen in cases of bacterial infection 4- Naked eye parasite Normal: no parasites or larva appear in the stool but in some cause the whole worm or part of its body appear in the stool and can be seen by naked eye like(segment of tap worm ) Two worms can be seen by naked eye in the stool: Ascaris lumbericoides and Entrobius vermicularis  5- Gross blood Normally no blood seen in the stool. Abnormal fresh blood (Hematochezia) seen in cases of lower GIT bleeding and also known as "bright red blood per rectum" 6- Mucus A small amount of mucus in the stool is normal, but excessive mucus can indicate inflammation or infection in the gastrointestinal tract. Mucus abnormally can be found in the stool in the following cases: Spastic colon (translucent mucus on the surface of stool) Ulcerative colitis Bacillary dysentery (mucus with fresh pus) Amoebic dysentery (mucus with fresh blood  Chemical Analysis pH is Normally variable and diet dependent and is based on bacterial fermentation in the small intestine. High alkaline stool- Physiological: cause by using High protein diet Pathological : Colitis or Antibiotic use (impaired colonic fermentation) High acidic stool- Physiological :High carbohydrate diet Pathological: Poor fat absorption Fat in stool Increased Fats is associated with Malabsorption Syndromes, such as Coeliac disease, Crohn’s disease, Enteritis and Pancreatic diseases, Surgical removal of section of Intestine, and others. The stool can be examined by the following techniques: 1. Saline wet mount examination: The stool is emulsified in normal saline and a large drop is placed on a glass slide and is then covered with a cover slide. Then examined under a light microscope, it is important to examine the specimen under a 10X objective lens at first to observe large molecules, cells, ova, and helminths, then to the 40X objective to complete the test. 2. Iodine examination: Iodine preparation leads to better visualization of morphological details of ova and cysts as it stains the glycogen in them. However, it has the disadvantage that the live trophozoites of Entamoeba histolytica and other live parasites cannot be seen as the iodine kills them.  Procedure for the microscopic examination of faecal samples for parasites 1. place a drop of saline 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. Using of Saline: Normal saline (0.85%) is used for routine examination of stool samples, as itis isotonic. Using of Iodine: Iodine is used to examine the nuclei of cysts. Under the microscope, we can observe the followings: (1) Pus cells: Observed in stool the same procedure as in urine. (2) RBCs: Observed in stool the same procedure as in urine. (3) Monilia: Observed in stool the same procedure as in urine. (4) Undigested Food Particles: Undigested food in the stool might suggest malabsorption or inadequate digestion (5)Mucus: Increased mucus can be a sign of inflammation or irritation in the digestive tract. (6) Protozoa (a) Entamoeba histolytica: To investigate the vegetative phase (trophozoite) and cyst, causing amoebic dysentery disease. (b) Entamoeba coli: trophozoite + cyst Note: - most of the children’s diarrhea is less than 2 years caused by Entamoeba coli. (c) Giardia lamblia, trophozoite + cyst, Cause watery diarrhea disease in children, especially. (d) Balantidium coli, trophozoite + cyst, causing Balantidiasis in the colon. (6) Worms: (a) Enterobius vermicularis (pinworm): investigating the eggs that are of a convex and flat surface and a pointed end. (b) Ascaris lumbricoides: investigating for eggs characterized by the content of granular yellow to Brown irregular albumin membrane. (c) Hookworm (Ancylostoma duodenale): investigating the eggs where the egg yolk is divided and surrounded by a thin membrane. (d) Tapeworms, (Taenia solium): investigating the worm pieces called (gravid segments or Proglottids) that come out with the feces. (e) Schistosoma mansoni: Investigating the eggs distinct by lateral spin Pictures of parasites in different stages as seen under microscope Entamoeba histolytica(cyst) Entamoeba histolytica (trophozoite) Giardia lamblia (cyst) Giardia lamblia (trophozoite) Enterobius vermicularis (Egg) Enterobius vermicularis (Adult) Ascaris lumbricoides Egg Schistosoma mansoni Egg Adults