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

3. General laboratory procedures 87Fig. 3.64 Autoclaving syringes and needlesInstallationAutoclaves should be installed away from the main working area, as they are noisy.If gas or a paraffin oil stove is used for heating, it should be kept away from flammablematerials and chemicals.Preparation of material for sterilizationReusable syringesReusable syringes are placed in large glass test-tubes plugged with non-absorbentcotton wool (the pistons and barrels in separate tubes; Fig. 3.64), or they are wrappedin gauze and placed in metal trays.Reusable needlesReusable needles should be placed separately in small test-tubes that arethen plugged (see Fig. 3.64). Place a pad of non-absorbent cotton wool atthe bottom of each tube to protect the tip of the needle.Otherwise, arrange the needles in metal trays with their points stuck into afolded gauze pad (Fig. 3.65).The metal trays are placed uncovered in the autoclave.GlasswareSpecimen tubes, Petri dishes, etc. should be wrapped in autoclavablepolyethylene bags and tied with string.Fig. 3.65 Alternative method forautoclaving needlesPasteur pipettes (Fig. 3.66)Pasteur pipettes should be placed in large tubes which are then plugged.Alternatively they may be placed in autoclavable polyethylene bags.Sterilization procedure1. Fill the bottom of the autoclave with water (up to the basket support).Make sure that the water does not touch the basket. If necessary, drainoff excess water by opening the drainage tap.2. Put the basket containing the material to be sterilized in the autoclavetogether with sterilization indicator papers. The indicator papers turnblack when the correct temperature is reached.Fig. 3.66 Autoclaving Pasteur pipettes