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b. Fold the tape over the near end of the slide and smooth the adhesive down along the full length
of the slide.
c. Attach a paper tab to the free end of the tape for labeling.
d. Store in the refrigerator.
- Collect the specimen
a. Using the paper tab, pull the tape back from the slide leaving the fold over the underside attached.
b. Loop the tape over a tongue depressor to hold it steady.
c. Press the sticky tape surface against the perianal skin. Press open the perianal folds to gain
access to eggs in the crevices.
d. Use a limited area of the tape surface to decrease the area for microscopic examination.
e. Smooth the tape back into place using a piece of cotton.
CAUTION: The eggs will stick to you and are infectious for several hours after being passed. - Perform a microscopic examination of the slide.
a. Lift the tape from the slide and place a drop of toluene or xylene on the slide. Smooth the tape
back into position.
NOTE: Slides may be stored up to several weeks in the refrigerator before being examined; however,
do not put the toluene or xylene on the slide until ready for examination because the chemicals will
distort the eggs.
b. Search the slide for eggs using low power magnification and reduced light. - Record and report the results.
Lab Procedure: Concentration Techniques for Ova and
Parasites (Con-Trate Method)
18D Skills and Training ManualWhen: To microscopically examine a fecal specimen for the presence of parasites and parasite ova.
What You Need: A properly collected fecal specimen, a Feka Con-Trate System containing: filtering
devices, disposable centrifuge tubes with caps, Muco Pen X (reagent A) and Ethyl Acetate (reagent B),
manufacturer’s instructions for Con-Trate Fecal Concentration; cotton tipped applicator sticks; microscope
slides; 22 x 40 mm coverslips; 10% formalin; a centrifuge; disposable transfer pipets; a tube rack; a squirt
bottle; Lugol’s iodine; a vortex mixer and a laboratory request form.
What To Do:
- Perform the concentration procedure.
a. Strain about 3 ml of the specimen suspension through the disposable filtering device into a 15
ml conical centrifuge tube.
b. Fill the tube to 12 ml with 10% formalin.
c. Centrifuge at 2000 rpm for 5 minutes.
d. Remove the tubes and pour off the supernatant.
e. Prepare slides for acid-fast bacteria (AFB) staining by placing 1 drop of the sediment on a glass
slide and allowing it to air dry.
f. Add formalin to the 8 ml mark on the tube.
WARNING: Formalin may be fatal if swallowed and harmful if inhaled. Exposure may create a cancer
risk and may cause blindness. Keep away from heat, sparks, or flame. Avoid breathing vapor. Use
only with adequate ventilation. Wash thoroughly after handling.
g. Add ethyl acetate to the 12 ml tube, stopper the tube, and vortex.
WARNING: Ethyl acetate is flammable. Keep away from heat, sparks, or flame. It is harmful if
swallowed or inhaled. Use only with adequate ventilation. Avoid contact with eyes. Wash thoroughly
after handling.
h. Allow the tube to stand for 3 minutes.
i. Centrifuge at 2000 rpm for 5 minutes.