I work in a vet clinic and we don't require yearly testing but the owners do have to sign a waiver stating they know the risks if they don't want the heartworm test. We used to do them every other year and then last year the American Heartworm Society said they had started to see an increased number of dogs on heartworm prevention that were testing positive so we started recommend yearly testing. I know I've been guilty of giving it a few days late myself so I think yearly testing is definitely a good idea. |