Macroscopic Examination of Stool

INSPECTION I. Macroscopic Examination of Stool 1. Immediately after the specimen is received at the laboratory, observe/examine: a. Consistency : solid/hard soft/soft liquid b. Color : green, brown, yellow, pale c. Mucus : present/absent (positive/negative) d. Blood : present/absent (positive/negative) e. Indigestible food f. Worm 2. Specimens containing blood and mucus must be examined first (priority I), followed by liquid specimens. These specimens often contain amoebic trophozoites (which die quickly after the stool is passed) so should be examined no more than 1 hour after the patient has passed the stool. Dense/hard specimens can be examined at any time on the first day of stool being passed but should not be later than 24 hours (overnight) because the cyst will be damaged. II. Microscopic Examination of Wet Preparations Wet smears are the easiest and simplest technique for stool examination and this method can be carried out in all laboratories in peripheral areas. Wet preparations can be prepared directly from fecal material or from concentrate specimens. The basic wet preparation methods that can be used for stool examination are saline, iodine, and methylene blue buffer -Saline wet preparations are used for preliminary microscopic examination of feces. This is done to show worm eggs, larvae, protozoan trophozoites and cysts. This dosage form can also display the presence of red blood cells and white blood cells. - Iodine wet preparation is mainly used for staining glycogen and cyst cell nuclei, if visible. Cysts can be specifically identified on this preparation - Wet preparationBuffered Methylene Blue(BMB) should be prepared any time amoebic trophozoites are visible on a saline wet mount or when amoebic trophozoites are suspected. BMB can stain amoebic trophozoites, but cannot stain amoebic cysts, trophozoites or flagellate cysts. BMB staining is useful only on fresh specimens that have not been preserved. This stain cannot be used on preserved specimens where the organisms have been killed. Materials and Reagents 1. Cover slip/deck glass 2. Bottle containing: saline solution, Lugol's isotonic iodine (1% solution) Buffered Methylene Blue 3. Object glass 4. Pen or marker for labeling 5. Coiled wire (or applicator stick, matchstick, or toothpick) Direct PreparationSalineAndIodine 1. With a pencil/marker, write the patient's name or number and date on the right side of the pageslides 2. Place 1 dropsalinein the middle of the left side and place 1 drop of solutioniodinein the middle of the right side ofslides. Note: if amoeba trophozoites are suspected, then use a warm saline solution (37°) 3. Using an applicator stick (match or toothpick), take a small amount of the specimen (about the size of a match stick) and mix with a drop saline. Notes : Hard stools:take feces from one point in the area covering the outside and inside of the specimen Stool with mucus:If there is mucus in the stool, label it on the side slidessecondly with the patient's name or patient number. Put one dropsaline onslides, take some slime and mix it withsalinethe. Trophozoites, if visible, are sometimes easier to find in mucus than in stool. Liquid stools:If there is no mucus, take a small amount of stool (from any part) and mix it withsaline. 4. As above, take a small portion of the stool and mix it with a drop of iodine solution to prepare an iodine preparation. If using wire, burn the wire after making preparations. If you use an applicator stick, throw it away after use. 5. Close the saline andiodinewhich has been mixed withcoverslip. Stand coverslipat an angle, touch one end with the drop and lower itcoverslipslowly. This will reduce the formation of air bubbles in the preparation. Perform steps 1-5 for ”direct preparationsaline Andiodine”, but place 1 large drop of BMB How to Check 1. Place the slide on the microscope and use 10x focus 2. Adjust the light so that it is aimed at the preparation. You must be able to see objects in your field of vision clearly. Too much or too little light will not be good. 3. Examine the entire visual field of the preparation with 10x magnification. Start from the top left corner then move the slide systematically to the right until the right peripheral then downwards, move the slide to the left until the left peripheral (zig-zag) 4. When a suspect organism or material is seen, change the focus and magnification and increase the lighting to see the morphology more clearly. This is a systematic examination. If the preparation is examined in this way, all parasites present will usually be found. If preparations are not checked systematically, parasites will sometimes be missed. Examine each field of view of the microscope carefully, focusinh up and down before moving to the next field of view