How is pinworm infection (enterobiasis) diagnosed?

Updated: Nov 21, 2018
  • Author: Sun Huh, MD, PhD; Chief Editor: Michael Stuart Bronze, MD  more...
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Answer

Glass slide microscopic analysis for Enterobius vermicularis may be performed looking for ova and female pinworms. A specimen is best obtained by dabbing the stretched, unwashed perianal folds in the early morning with cellophane tape and affixing the specimen onto a slide. A negative test for 5 consecutive mornings effectively rules out the diagnosis.

Microscopic examination shows the elongated ovoid egg distinctly compressed laterally and flattened on one side. The egg measures 50-60 µm X 20-30 µm and contains larva.

In areas where pinworms are endemic, consider analyzing any removed appendiceal stump for infestation. [7]

Patients with recurrent episodes of perianal itching should have a stool sample sent to the laboratory for analysis because different parasites, which require different treatment, may appear similar to E vermicularis using the cellophane-tape test. [8]


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