I recently bought this kit and love it! It has saved me a lot of money and helped me to get a better picture of what is going on inside each individual horse.
The McMaster FEC technique is a quantitative test that is utilized by most veterinary diagnostic labs including Idexx and a majority of the universities.
Centrifugation using the Wisconsin sugar method is more sensitive but requires more time and money. Additionally, since we are only trying to get a general picture of the worm burdern we donít need to know if there are less than 25 eggs per gram (sensitivity cut off for McMaster technique). The recommendation is to treat with dewormer when your egg counts are >200 so who cares about a possible variation of 25 in each direction?
I used to work in a veterinary diagnostic lab in the southeast and this is the "gold standard" test that we used for submitted samples.