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Pinworm Exam

Enterobius vermicularis, enterobiasis, Scotch tape prep, Pinworm Examination

Test Codes

EPIC: LAB248

Department

Microbiology

Instructions

Pinworms usually migrate to the anus and lay eggs during the night. Therefore, specimens should be collected when the patient first awakens in the morning, before the patient defecates or bathes.

Specimen Collection Criteria

Collect: Pinworm eggs from the perianal region using the cellophane tape (placed on a glass slide in sterile collection container) or paddle method. Please see Testing for Pinworm Instructions.

Note: A minimum of four to six consecutive negative tape preps are required to rule out the infection.

Physician Office/Draw Specimen Preparation

Maintain specimens at room temperature (20-26°C or 68-78.8°F) prior to transport.

Preparation for Courier Transport

Transport: Slides containing cellophane tape, or pinworm paddle, at room temperature (20-26°C or 68-78.8°F).

Rejection Criteria

• Specimens not collected and processed as indicated.
• Fecal or other specimens will not be tested without consultation with the Microbiology Medical/Technical Director.

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 7 days
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Room Temperature (20-26°C or 68-78.8°F): 7 days

Laboratory

Royal Oak Microbiology Laboratory

Performed

Monday – Friday, 7:00 am – 3:30 pm.
Results available within one business day.

Reference Range

No pinworm eggs detected.

Test Methodology

Microscopic examination, unstained.

Interpretation

Presence of Enterobius vermicularis ("pinworm") eggs indicates infection.

Clinical Utility

This assay aids in the diagnosis of pinworm infection.

Clinical Disease

Pinworm infection is caused by the nematode, Enterobius vermicularis. Pinworm infection (enterobiasis) causes pruritus ani and, rarely, pruritus vulvae. Although pinworms have been found in the lumen of the appendix, most evidence indicates that they are not causally related to acute appendicitis. Many symptoms, such as grinding of the teeth at night and enuresis, have been attributed to pinworm infections, but proof of a relationship has not been established. Vaginitis, salpingitis, and pelvic peritonitis can occur because of aberrant migration of the adult worm from the perineum (1).

Epidemiology

Enterobiasis is distributed worldwide and usually occurs in family clusters. There is no sex preference or seasonal variation in disease incidence. In the past, 5% to 15% of the population of the United States was thought to be infected, but the incidence has declined recently. Prevalence rates are higher in preschool-aged and school-aged children, in mothers of infected children, in daycare nurseries, and in institutionalized individuals where up to 50% of the population may be infected (1) (2).

Incubation Period

The time from ingestion of an egg until an adult gravid female migrates to the perianal region is 1 to 2 months or longer (1).

Transmission

Transmission occurs by multiple routes, the primary of which is fecal-oral, with worm eggs transmitted by fingers and hands and via shared toys, bedding, clothing, toilet seats, and baths. Adult gravid female nematodes usually die after depositing eggs on the perianal skin. Thus, reinfection by autoinfection or exposure to eggs from other individuals is necessary to maintain enterobiasis in an individual. The condition is communicable as long as the gravid female nematodes are discharging eggs on perianal skin. Eggs are infectious in an indoor environment for 2 to 3 weeks. Humans are the only hosts (1).

Reference

1. Chin, J. 2000. Enterobiasis. Control of Communicable Diseases Manual. APHA: Washington, D.C., pp. 186-188.
2. Sheorey, H., B. Biggs, & P. Traynor. 2011. Nematodes. In: Versalovic, J. et. al. (eds.). Manual of Clinical Microbiology. 10^th ed. ASM Press. Washington, D.C.

CPT Codes

87172

Contacts

Last Updated

11/12/2024