RVC/FAO guide to Veterinary Parasitology
McMaster egg counting technique: Calculation of results

The number of eggs per gram can be calculated as follows:

  • Count the number of eggs within the grid of each chamber, ignoring those outside the squares
  • Multiply the total by 50 – this gives the eggs per gram of faeces (e.p.g.)

For example:

Egg counting

12 eggs seen in chamber 1 and 15 eggs seen in chamber 2

= (12 +15) x 50 = 1350 e.p.g.


Warning !!!

Do not delay reading the count beyond the recommended time as
the flotation fluid may distort or destroy delicate eggs.

Therefore it is advisable to only process a few samples at a time.