Restool examination The final examination is carried out in laboratories for various diagnostic purposes. Stool routine test helps in the diagnosis of diarrhea, dysentery, malabsorption, gastrointestinal tract bleeding and parasitic infections. Collection of the stool specimen The feces for the microbiological examination should be collected during the acute stage of the diureal disease. Press the patient to pass the stool sample in a clean, dry, disinfectant-free, suitable white-necked container or a plastic cup with a tight-fitting lid. About 20-40g of well-formed stool or 5-6 ml of watery stool will suffice for a routine examination. The injection of some medicines prior to the collection of the fecal sample may interfere with the detection of the microorganisms. All specimens must be properly labelled with the patient's name, age, sex and the date of the sample collection. Precautions Do not keep the specimen at warm temperatures. Try to keep it in cool places. Prevent the drying of the specimen. Prevent its contamination with urine or dirt particles. The stool should not be collected from bedpants which contain disinfectants. Note, the specimen must reach a laboratory within 30 minutes of passing of the stool, since the motile organisms, for example, vibrio and amoebic trophazoids, are heat sensitive and can die or become unrecognizable after that period. Here for specimen rejection are, specimen contaminated with urine, residual soap or disinfectants, specimens received in grossly leaking transport containers, dry specimens and specimens submitted in fixative or additives. Equipment Glass slides Normal saline Lugals iodine Saturated saline solution Applicators sticks Test tubes Microscopic examination The laboratory diagnosis of most parasitic infections is by the demonstration of over and cysts of the parasite in the stools of the infected person. The stool can be examined by the following techniques, wet mount examination, iodine preparation and concentration techniques, saline specimen preparation. Place a drop of normal saline on a labelled glass slide. Using an applicator stick, transfer a small portion of the stool from the muquite or blood or particulate matter in a watery stool and mix well in the saline. Place a cover slip over it without any air bubbles and examine immediately. Iodine specimen preparation Place a drop of Lugals iodine on a labelled glass slide. Using an applicator stick, transfer a small portion of the stool from muquite, blood or particulate matter in a watery stool and mix well in the saline. Place a cover slip over it without any air bubbles and examine immediately. Concentration method If the number of parasites in the stool specimens is low, the examination of a direct wet mount may not reveal them and hence the stool should be concentrated. Fill a test tube half with saturated saline. Add a small amount of stool in it and emulsify well with an applicator stick. Fill the tube to the brim with saturated saline. Cover with a glass slide touching the surface of the mixture. Leave undisturbed for 15 minutes. Remove the slide without spillage. Place on a flat surface and cover the area smeared with the sample with a cover slip, taking care to avoid air bubbles. Examine under the microscope. To examine the slide. Put the slide with the mounts on the microscope stage and focus on the mount with the low power objective first. Systematically scan the entire cover slip area using the 10x objective in a zigzag manner. If something suspicious is seen, a higher magnification may be necessary. Note, it is preferable to keep the condenser down and the intensity of the light low for proper visualization of the over and cysts. Quality control Split sample testing should be performed monthly on the same sample by two technicians. The lab comparisons is another method of ensuring quality control.