What are the microscopy findings in the workup of strongyloidiasis?

Updated: Jun 20, 2019
  • Author: Pranatharthi Haran Chandrasekar, MBBS, MD; Chief Editor: Michael Stuart Bronze, MD  more...
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Answer

Microscopically identify Strongyloides stercoralis larvae (definitive diagnostic test). The larvae resemble those of hookworms, but they can be distinguished by their short buccal cavity.

Examine stool directly in wet mounts (very low yield) (see the image below) or after ethyl acetate-formalin concentration occurs.

Rhabditiform larva of Strongyloides stercoralis in Rhabditiform larva of Strongyloides stercoralis in stool specimen (wet mount stained with iodine).

Several fresh stool specimens may need to be examined before a positive result is found. Single stool examination yields a low sensitivity (approximately 30%) in chronic strongyloidiasis, because larval output is low and intermittent. Thus, perform at least 3 stool examinations on consecutive days, because this may increase the sensitivity to 70-80%. More than 90% sensitivity for stool samples is seen if 7 or greater samples are examined.


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