Which diagnostic test is used to reliably diagnose Enterobius vermicularis in school-aged children?

• A. Stool examination for eggs
• B. Blood antibody testing
• C. Perianal cellophane/adhesive tape test
• D. Urine antigen testing

Answer: (C)

Diagnosing pinworm infections hinges on finding the eggs where the worms actually deposit them: around the anus. In school-aged children, female worms lay eggs at night, so the most reliable method is a perianal adhesive tape test. The tape is pressed to the skin around the anus in the morning before washing, and then the eggs collected on the tape can be examined under a microscope. This approach is more sensitive for Enterobius vermicularis than looking in stool, because the eggs are shed primarily from the perianal area and may not appear consistently in stool samples, and adult worms are not always present in the stool. Blood antibody testing isn’t helpful for current pinworm infection since antibodies reflect exposure and can persist after the infection clears. Urine antigen testing isn’t used for pinworms because there isn’t a valid antigen test for this parasite. So the perianal adhesive tape test directly targets where the parasite lays eggs and is the most reliable diagnostic method in children.