Method:
(1) 4 mL (approximately 4 grams) of stool is mixed with 56 mL of 0.1N NaOH for a final volume of 60 mL in a sealable flask.
(2) Glass beads are added to the flask, which is then sealed.
(3) The flask is shaken vigorously until all of the fecal material is broken up and emulsified.
(4) 0.075 mL (75 microliters) of the emulsion is withdrawn and placed in a counting chamber.
(5) The number of eggs on the slide is counted.
dilution of the emulsion =
= 4 / 60 * 0.075 = 0.005 = 1 / 200
number of eggs per gram of feces =
= (number of eggs counted) * 200
The amount of water in the stool effects the concentration of eggs. This can be corrected for by adjusting the raw count for the stool consistency.
adjusted number of eggs per gram of feces =
= (number of eggs per gram of feces) * (consistency factor)
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Stool Consistency
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Consistency Factor
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firm
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1
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mushy and formed
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1.5
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mushy
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2
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mushy diarrhea
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3
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flowing diarrhea
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4
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watery
|
5
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