STEP 4: Either replace the tape on the tongue depressor for transportation to the
laboratory or place the "Scotch tape" on a 25 by 75 millimeter glass slide,
sticky side down.
STEP 5: Smooth the tape with cotton or gauze.
STEP 6: Examine the slide under the low power objective of the microscope and
STEP 1: Prepare a paraffin/vaseline mixture in a 1:4 ratio and coat swabs with the warm
mixture. Allow the swabs to cool.
STEP 2: Holding the swab with the right hand, spread the buttocks with the left hand
and gently swab the perianal region with the coated swab.
STEP 3: Place the swab in a 13 by 100 tube to which two or three milliliters of Xylol has
been added. Allow to stand for three to five minutes.
STEP 4: Twirl the swab in the Xylol, hold it against the sides of the test tube, and
express the liquid; discard the swab.
STEP 5: Centrifuge the test tube at 2,000 rpms for two to four minutes.
STEP 6: Remove the supernatant by aspiration and transfer the sediment to a slide.
Examine the specimen under the low power objective and identify any ova
recovered under the high dry.
(3) Duodenal contents. Parasites that inhabit the small intestines are easily
overlooked when examining a stool sample. Consequently, when Giardia lamblia or
Strongyloides stercoralis are suspected, the duodenal content examination will be the
test of choice. Duodenal intubation causes much discomfort to the patient; therefore, it is
not a desirable procedure. In its place, the string capsule technique (described by Beal,
et al, in 1970) offers an easy and almost painless method of examining duodenal
contents. A gelatin capsule containing a line of 25 centimeters silicon thread covered
with rubber and a 75-centimeter soft nylon yarn are used in this procedure. The patient
swallows the capsule containing the string and a lead weight that helps the capsule to
move to the duodenum (the end of the string that sticks out is held fast by taping it to the
patient's neck). After three to five hours, the string is pulled out (the weight separates
from the capsule and it is excreted), the portion of the string that has bile-stain contents is
scraped off, placed on a slide, and examined for protozoan cysts and trophozoites or
helminthes eggs and larvae.