I agree, it would be beneficial to have the paperwork or at least contact info for the vet your rescue organization used to administer the injections. I think the confusion comes in because the “standard protocol” now calls for the 3 injections vs. 2. But both are effective depending on the worm infestation level. If the dog has already been subjected to 2 injections (as confirmed by the vet who administered)…it doesn’t make sense to start over from the beginning and give 3 more! Unfortunately, it takes 6 months before you can re-test to know whether the treatment has been effective. I would also agree with your decision to switch vets to one who knows about/treats heartworm disease.
