My Eddy has Feline Leukemia ever since we got her.

What they do, is they take a drop of blood from a paw. It's very simple and doesn't really hurt your kitty.
This drop goes on a Fel-V tester unit. It looks like a pregnancy test, with 2 screens. The results show in a few minutes.
There's also a test where they send a bloodsample to a bloodlab, but this is actually not really needed in my opinion and is also very expensive.

There are kitties that get over it and are tested negative the second time. My Eddy didn't.

I should actually seperate Eddy and Rudie, but I don't. Rudie only survives because of Eddy. They don't share eating/drinking bowls though.

What the vet told us at the diagnose, was that it was important for Eddy to live a stress-free life and sleep a lot. And so it be. She sleeps most of the day, only goes into our garden if she wants to go out and is checked every 6 months for signs of the leukemia. I hope this will never happen, since many kitties live a normal life and grow very old.

Rudie gets an extra boost, although there is actually no real vaccination. But he's free and strong as a horse (knock on wood).

If you have other cats, they should be tested too.

Good luck, and let us know the results.

PS. The test is quite expensive. Last time I payed about 70 dollar for both kitties.