Microbiology Laboratory

WET MOUNTING/PREPARATION for parasites

Written by MicroDok

Wet mounting is a direct microscopic examination of feacal specimens.

AIM: To detect the presence of motile parasites, white blood cells (WBC), red blood cell (RBC), casts, cysts, and eggs of parasites, as an aid in the diagnosis of helminthic infections.

MATERIALS/APPARATUS: Stool specimen, binocular microscope, glass slides, cover slip, bulb pipette physiological/normal saline, applicator stick, cotton wool, discard jar.

METHOD/PROCEDURE:

  1. Place 2 drops of normal saline on a clean glass slide using a bulb pipette.
  2. Using the applicator stick, collect a small amount of the feaces and mix it with the normal saline on the glass slide.
  3. As you emulsify/mix the feacal specimen and the normal saline together, make sure that a thin smooth preparation is made. Otherwise, the preparation will be too thick, making it difficult to detect and identify parasites or any of its components present in the specimen.
  4. Cover the preparation/mixture on the glass slide with a cover slip.
  5. Examine the prepared slide under the microscope using ×10 objective lens to focus, and then ×40 objective lens to confirm.

Note:  The condenser iris of the microscope should be closed sufficiently before viewing in order to get a very good contrast. Also, always make sure that you examine several fields of the slide before making your final report, so as to clear all doubts.

REPORTING OF THE RESULT:

Report the appearance of the stool specimen first based on its colour and consistency. Report the number of larvae and egg/ova found as: scanty, few, moderate number, many, or very many. The presence of WBC, RBC, or cysts is also reported using + sign, and if not found in the specimen; they are reported as “nil”.

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