PINWORM EXAMINATION

Effective Date: 
Thu, 08/01/2013
Reviewed: 
Tue, 01/10/2017
Revised: 
Thu, 08/01/2013
Policy: 

 

Purpose and Scope:

Enterobius vermicularis, the causative agent of human enterobiasis, is a parasitic helminth that is widely distributed throughout the population. Because only five to ten percent of infected persons have demonstrable eggs in their stools, specimens must be collected from the perianal region. It is to this area that the gravid female migrates and lays large numbers of eggs while the host is resting.

The sticky side of a SWUBE Pinworm Paddle is applied to the perianal area to collect the specimen. The paddle can be removed from the cap and  examined directly under a low power microscope for the presence of eggs or adult female worms.

 

Reagents and Supplies:

 

  • Falcon SWUB Pinworm Paddle
  • Patient Instruction Sheets
  • Microscope

 

Procedure

 

Patient Instructions

  1. Hold the paddle by the cap and remove it from the tube.
  2. Separate the buttocks and press the tacky surface against several areas of the perianal region.
  3. Replace the paddle in the tube for transport to the laboratory; specimens should be refrigerated if examination is to be delayed for more than one day.

 

 

Lab Instructions

Remove the paddle from the cap and utilize it as a slide for direct low power microscopic examination of the specimen.

Interpretation of Results

E. vermicularis eggs measure 50 – 60 μm in length and 20 – 30 μm in width and are elliptical-ovoid in shape with a thick, smooth colorless shell.

Occasionally adult female worms may be observed. Female worms are transparent and measure 8 – 13 mm in length and 0.5 mm in diameter; they possess a ventrally curved posterior end, long, narrow, sharply pointed tail, and cephalic alae or wings at their anterior end.

 

 

REFERENCES

Balows, A., W.J. Hausler, Jr., M. Ohashi and A. Turano (ed.). 1989. Laboratory diagnosis of infectious diseases, vol. 1. Springer-Verlag, New York.

Wentworth, B.B. (ed.). 1988. Diagnostic procedures for mycotic and parasitic infections,

7th ed. American Public Health Association, Inc., Washington, D.C.

Murray, P.R., E.J. Baron, M.A. Pfaller, F.C. Tenover and R.H. Yolken (ed.). 1995.

Manual of clinical microbiology. 6th ed. American Society for Microbiology, Washington, D.C.

Baron, E.J., L.R. Peterson, and S.M. Finegold. 1994. Bailey & Scott’s diagnostic microbiology, 9th ed. Mosby-Year Book, Inc., St. Louis.

Isenberg, H.D. (ed.). 1992. Clinical microbiology procedures handbook, vol. 2. American Society for Microbiology, Washington, D.C.