Stoll Egg Counting Technique
A method for determining the number of nematode eggs per gram of feces in order to
estimate the worm burden in an animal. The advantage of this technique is that it requires
no specialized equipment, the disadvantage is the counting takes a long time because of
the amount of extra (nonegg) material on the slides.
 Weigh out 3 grams of feces.
 Measure out 42 ml of water and place it into a dish. Using a tongue depressor, push
the 3 grams of feces through a sieve into the water. Lift the sieve and hold over the
dish. Push out any remaining water from the feces.
 While stirring the waterfeces mixture, take 0.15 ml of the suspension and spread
over 2 slides. Cover each slide with a long coverslip (or 2 regular size coverslips).
 Examine both slides for worm eggs, the total number of eggs counted X 100
represents the number of eggs per gram of feces.
 Since 0.15 ml is 1/300 of 45 ml (42 ml water and 3 gm feces) then
the number of eggs in 0.15 ml X 100 is equal to 1/3 of the total number of eggs in the
original 3 grams and thus equal to eggs per gram (EPG).
