How can I tell if the dewormer I used on my kittens is working?

how can i tell if the dewormer i used on my kittens is working?
They should poop out a sack of worms within 3 to 4 days

After the first dosage or after the other 2 dosages that they are suppose to take?

I never had cats with worms before. But when my dogs had them when we finished up the medicine within a week there was no worms in their poo. Btw they way with my dogs I gave 1 dose 3 days in a row.