Manual of basic techniques for a health laboratory - libdoc.who.int

142 Manual of basic techniques for a health laboratory●●●●●Flat-bottomed jarForcepsToilet paper or absorbent tissueScrap paper (e.g. newspaper)Glycerol–malachite green solution (reagent no. 31) or methylene blue solution(reagent no. 39).MethodImportant: Care must be taken to avoid contamination during collection of stoolspecimens. Always wear gloves.1. Soak the cellophane strips in the glycerol–malachite green (or methylene blue)solution for at least 24 hours before use.2. Transfer a small amount (approximately 0.5g) of faeces on to a piece of scrappaper (newspaper is ideal).3. Press the screen on top of the faecal sample.4. Using the applicator stick, scrape across the upper surface of the screen to sievethe faecal sample (Fig. 4.78).5. Place the template on a clean microscope slide. Transfer the sieved faecal materialinto the hole of the template and level with the applicator stick (Fig. 4.79).6. Remove the template carefully so that all the faecal material is left on the slideand none is left sticking to the template.7. Cover the faecal sample on the slide with a glycerol-soaked cellophane strip(Fig. 4.80).8. If any glycerol is present on the upper surface of the cellophane, wipe it off witha small piece of absorbent tissue.9. Invert the microscope slide and press the faecal sample against the cellophaneon a smooth surface (a piece of tile or flat stone is ideal) to spread the sampleevenly.Fig. 4.78 Using an applicator stick, scrape across the upper surface of the screen to sievethe faecal sample