Modified McMaster's technique for fecal egg counting
Materials
- Wooden tongue depressors
- Sheather's sugar solution (recipe below)
- Tea strainers
- Graduated cylinder
- Glass beakers
- Transfer pipettes
- McMaster slides
- Small weigh boats
Equipment
- Microscope
- Scale
Protocol
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Weigh out 2 grams feces per sample.
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Measure out 25 mL of Sheather’s sugar solution using a graduated cylinder.
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Place a tea strainer on top of a 100 ml beaker and add the feces to the strainer.
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Pour the sugar solution incrementally over the feces and muddle/squeeze the feces through the strainer using a tongue depressor.
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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.
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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).
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Let the slide sit for 5-15 minutes for the eggs to float.
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Using a microscope, count the total number of eggs under both grids.
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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
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Combine 454 g granulated sugar and 355 mL water.
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Heat while stirring until dissolved (preferably in a double boiler).
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Add 6 mL of 37% formaldehyde or formalin.