A 12-year-old child from a tribal region presents with perianal pruritus worst at night, and the mother reports seeing small white thread-like worms near the anus. The most reliable diagnostic test is:
- A Stool microscopy for ova
- B Peripheral blood eosinophil count
- C Scotch tape (cellophane) test performed in the morning before bathing ✓
- D Serological ELISA for Enterobius vermicularis
Correct answer: C. Scotch tape (cellophane) test performed in the morning before bathing
Explanation
Enterobiasis (pinworm, Enterobius vermicularis) is best diagnosed by the Scotch tape/cellophane tape test, where a piece of transparent adhesive tape is pressed against the perianal skin in the early morning before bathing or defecation, then examined microscopically for characteristic football-shaped eggs (plano-convex on one side). Stool microscopy has low yield because eggs are deposited perianally, not in stool. Eosinophilia is generally absent in intestinal pinworm infection as there is no invasive phase. No reliable serological ELISA exists for pinworm.
Reference: Ghai Essential Pediatrics, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.