PINW - Clinical: Pinworm Exam, Perianal

Test Catalog

Test Name

Test ID: PINW    
Pinworm Exam, Perianal

Useful For Suggests clinical disorders or settings where the test may be helpful

Detection of the eggs of Enterobius vermicularis on the skin of the perianal folds

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Enterobius vermicularis (pinworms) are nematodes (roundworms) which are found worldwide in both temperate and tropical areas. The adults reside in the upper large intestine of humans and transmission is by the fecal-oral route. Adult females migrate to the perianal area, especially during the night, and deposit large numbers of eggs.


Pinworm infection is the most common helminth infection in the United States and is the most common in young school-age children of all social classes. Pinworms do not produce significant intestinal disease but can cause irritating pruritus in the perianal area. They have also been implicated in vulvovaginitis in pre-pubertal girls and possibly in urinary tract infections.


Several agents are effective in treating pinworm infection (pyrantel pamoate, mebendazole), and good personal hygiene will prevent transmission of the eggs.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Negative (reported as positive or negative)

Interpretation Provides information to assist in interpretation of the test results

Positive results are provided indicating the presence of eggs of Enterobius vermicularis.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Although adult pinworms and eggs can occasionally be observed in stool specimens, examination of feces is not the optimum method for detecting those parasites.

Clinical Reference Recommendations for in-depth reading of a clinical nature

Mahmoud AAF: Intestinal nematodes (roundworms). In Principles and Practice of Infectious Diseases. Fourth edition. Edited by GL Mandell, RG Douglas Jr, JE Bennett. New York, Churchill Livingstone, 1995, pp 2526-2530

Special Instructions and Forms Library of PDFs including pertinent information and consent forms, specimen collection and preparation information, test algorithms, and other information pertinent to test