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

80 Manual of basic techniques for a health laboratoryWiping and dryingWipe the slides, one at a time, with a soft, non-fluffy cloth. Place them on a sheet offilter paper, one by one. Leave to dry. Examine each slide. Discard any slides thatare stained, scratched or yellow or that have dull patches on them, or try to cleanthem again.Wrapping upDivide the slides into piles of 10 or 20 and wrap each pile in a small sheet of paper.NumberingIn some laboratories the slides are numbered in advance in series of five packetswith a diamond pencil. (For example, for packets containing 20 slides each, theslides are numbered 1–20, 21–40, 41–60, 61–80 and 81–100, respectively.)Dirty slidesSlides covered with immersion oilTake the oily slides one by one and rub them with newspaper to remove as much ofthe oil as possible.Slides with coverslipsUsing the tip of a needle or forceps, detach the coverslips and drop them into abeaker of water (Fig. 3.60) (for cleaning of coverslips, see overleaf).Fig. 3.60 Removingcoverslips from aslide for cleaningSoaking in detergent solutionPrepare a bowl of cold or lukewarm water mixed with detergent. Use the amountrecommended by the manufacturer to produce a strong detergent solution.Leave the slides to soak for 24 hours.Note: Detergents containing enzymes are excellent for removing blood films.When slides have been used for infected specimens (e.g. urine, stools), they shouldbe placed in disinfectant solution before cleaning.CleaningAfter the slides have soaked for 24 hours, prepare another bowl containing a weakdetergent solution (15ml of household detergent per litre of water).Remove the slides one by one from the strong detergent solution.Rub each one with cotton wool dipped in the strong detergent solution, then dropinto the bowl of weak detergent solution and leave to soak for 1 or 2 hours.RinsingPreferred methodRemove the slides one by one from the weak detergent solution using forceps. Ifyou must use your fingers, pick the slides up by their edges. Rinse each slide separatelyunder the tap, then soak for 30 minutes in a bowl of water.Quick methodEmpty the bowl of weak detergent solution and fill with clean water. Change thewater three times, shaking the bowl vigorously each time.Wiping, drying and wrapping upFollow the instructions given above for new slides.