Heartworm Testing and Prevention: Why the Test Always Comes First
Testing Before Starting Prevention
Every dog needs a heartworm test to confirm they're free of an active infection before starting or renewing prevention. Giving medication to a dog with an existing infection can lead to serious complications, so this step matters even for dogs already on a preventive, since missed doses or delayed refills can create gaps.
A few situations call for testing: your dog is due for their annual wellness exam, starting heartworm medication for the first time, a dose was missed or given more than a couple weeks late, or your dog is switching to a different prevention product.
Choosing a Prevention Product
Chewable, topical, or a six-month injection, the right choice is less about brand and more about your pet's life. A dog who spends weekends at the lake needs something that won't wash off. A cat who's a master at dodging pills needs a topical instead. Age and weight matter too, so we weigh your pet at every visit, not just the first one.
If your puppy is younger than 7 months old, the American Heartworm Society doesn't require a blood test before starting prevention, since infection can't be detected that early.
The Testing Visit and Where to Go
We start with a quick chat about your dog's history and any symptoms, then a small blood sample from the leg. Results usually come back the same visit through our in-house lab. If it's negative, which it is for most dogs who've stayed on schedule, we get you set up with medication before you leave.
Our Petfolk Veterinary & Urgent Care - Sugar Land at 15890 Southwest Fwy #100 runs same-visit heartworm testing, which matters in a climate like ours where mosquitoes stay active most of the year.
Frequently Asked Questions
Heartworm Prevention