Updated On September 23rd, 2025
Pet's info: Dog | Mixed Breed | Female | spayed
I might have accidentally skipped Heartgard for 1 month. Not positive, but the following month when I went to give it, the pre-written month on the package didn't match and made me think I might have forgotten (unless I just randomly grabbed one the month before). I read that a blood test won't detective heartworms until 6 months later. My dog's annual is around then. Should I wait until then and see, or is there something I should do sooner?
2 Answers
Published on December 17th, 2018
If you only missed 1 month, you should be fine. Just resume Heartgard right away . If you just want peace of mind, then you can have Lilly retested in 6 month from now; however, the chances of infection are pretty low. Thanks for visiting Petco Pet Education Center, formerly Petcoach and best wishes with your pet Lilly. Take care!
2Pet Parents found this answer helpful
Published on November 6th, 2019
If it has been 6 months or more since the missed dose it is best to re-test for Heartworm before starting preventative. If it has been less than 6 months it’s okay to go ahead and start the medication. It takes 6 months for heartworms to mature and the test only looks for adult heartworms, so even if a dog has been infected with heartworms the test will be negative for the first 6 months.
1Pet Parents found this answer helpful
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