How is my cat tested for heartworm disease?

Typically, if we suspect a cat has heartworm, we will recommend a test just like in a dog. Most of the time, it comes out negative because, once again, that test tests for adult heartworms, which it's not usually adult heartworm that causes a problem in a cat. There aren't tests out there for immature stages. We sometimes test for antibodies. However, though they can develop antibodies a couple of months after infection, they are very transient. They go away really quickly, so we have a short window to catch them. That only means exposure and not necessarily that the cat is continuing to be infected as well. We will often look at x-rays, and we can see changes in the lungs that are highly suspicious of heartworm.

We draw a couple of drops of blood and that's all it takes. It takes about 10 to 15 minutes or we send it out to the lab.