Microscopic Examinatio

• What are the 3 test done under microscopic examination of stool samples?

  Direct Wet Mount, Special Stains, and Cellophane technique
• Direct Wet Mount: for eggs/larvae of HELMINTHS and cysts/trophozoites of PROTOZOA
• If direct wet mount is NEGATIVE, proceed to what?

  Concentration technique
• TRICHROME STAIN: identification of TROPOZOITES and CYSTS
• AFB stain: for OOCYTES of CRYPTOSPORIDIUM, CYCLOSPORA, and ISOSPORA
• Wright's stain: for WBC
• Cellophane technique: for eggs of ENTEROBIUS VERMICULARIS
• SALINE WET MOUNT: for trophozoites, cysts of protozoa, ova/larvae of helminths
• IODINE WET MOUNT: for identification of PROTOZOAN CYSTS
• A drop of normal saline is placed near one end of a glass slide and a drop of Lugol iodine is placed near the other end.
• A small amount of feces is mixed with a drop of saline and iodine using a wire loop, and a cover slip is placed over each preparation separately.
• If the specimen contains blood or mucus, that portion should be included for examination because TROPOZOITES are more readily found in mucus.
• If the stools are liquid, select the portion from the SURFACE for examination.
• Saline wet mount is used for demonstration of eggs and larvae of helminths, and trophozoites and cysts of protozoa.
• Saline wet mount can also detect RED CELLS and WHITE CELLS.
• The iodine wet mount is useful for identification of PROTOZOAL CYSTS as iodine stains GLYCOGEN and NUCLEI of cysts.
• Trophozoites become NON-MOTILE in iodine mounts.
• A liquid, diarrheal stool can be examined directly without adding SALINE.
• Normal stool may contain occasional how many WBCs?

  0-1
• To look for WBCs, the smears should be prepared from areas of MUCOUS or WATERY stools.
• Macrophages: seen in BACILLARY DYSENTERY and ULCERATIVE COLITIS
• EPITHELIAL CELLS: Seen in inflammatory conditions of the bowel.
• Stool cultures are commonly done to identify bacteria associated with ENTERIC INFECTIONS.
• At least how many stool cultures should be collected on separate days if the patient's clinical picture suggests bacterial involvement, despite previous negative cultures?

  3
• FAT: Present in malabsorption, deficiency of pancreatic digestive enzyme, and deficiency of bile
• MEAT or MUSCLE FIBERS: their presence show impaired INTRALUMINAL DIGESTION
• ARTIFACTS can be confused with what?

  ova and cysts
• Pollen grains in stools can be mistaken for what?

  Helminth eggs