Skip to content

Modified McMaster's technique for fecal egg counting


  • Wooden tongue depressors
  • Sheather's sugar solution (recipe below)
  • Tea strainers
  • Graduated cylinder
  • Glass beakers
  • Transfer pipettes
  • McMaster slides
  • Small weigh boats


  • Microscope
  • Scale


  1. Weigh out 2 grams feces per sample.

  2. Measure out 25 mL of Sheather’s sugar solution using a graduated cylinder.

  3. Place a tea strainer on top of a 100 ml beaker and add the feces to the strainer.

  4. Pour the sugar solution incrementally over the feces and muddle/squeeze the feces through the strainer using a tongue depressor.

  5. Once as much as possible of the feces have been passed through the strainer, add a stir bar and allow the solution to mix thoroughly.

  6. While solution is stirring, draw up suspension in a transfer pipet and transfer it to both chambers of a McMaster Slide (ensuring no bubbles are in the grid region).

  7. Let the slide sit for 5-15 minutes for the eggs to float.

  8. Using a microscope, count the total number of eggs under both grids.

  9. Multiply the number counted by 100 to get the number of eggs per gram (EPG) of feces (2 grams / 60 mL * 0.3 mL under two grids = 1/100 final dilution).

Recipe for Sheather's sugar solution

  1. Combine 454 g granulated sugar and 355 mL water.

  2. Heat while stirring until dissolved (preferably in a double boiler).

  3. Add 6 mL of 37% formaldehyde or formalin.