Blue Kitty is a "stray". He's been living at the same place for months, and they like him, and they feed him, but… he's pretty independent. Not the kind of cat that wants to come in and sit on your lap. Really, he's about half wild. Under those circumstances, he doesn't exactly get a thorough physical exam every day. In the last couple of days, they noticed that he just wasn't himself, just eating a little bit. That's why they scooped him into the carrier and brought him in.
Really, he's more than half wild. His goofy expression here is due to the fact that he had to be sedated to handle him, much less do any kind of real examination. He's messed up on dope. He's messed up on a bunch of other stuff, too. He's pretty thin, about 20% underweight (which is a lot) and about 5% dehydrated. He's been feeling bad for more than just two days; at least, he's been in ADR mode ["Ain't Doin' Right"] for longer than that.
He really stinks, too, and this mouth is why. Not only is there a lot of tartar, his gums are oozing pus and blood around almost every tooth. When you see a cat with such terrible gum disease and some major ADR, you have to wonder if this guy has a normal body defense system. I mean, there HAS to be a reason when somebody looks like this. This is beyond mere dental hygiene problems.
And here you have his little SNAP test. The blue spot on top is the positive "control" that lets you know the test is working properly, and the blue spot on the right is the one that lets you know Blue Kitty's blood is full of Feline Leukemia Virus. Few cats get the actual leukemia that gives the virus its name. Most just have their immune system shot to hell, like a person with HIV and AIDS. Then they sort of waste away, or start to have a lot of weird infections that shouldn't really be bothering them, like Blue Kitty's mouth problem.
Prognosis: poor. That's why you run this test before you advise the client to jump in with both feet, guns blazing and checkbook open wide. They need to know that you may be able to help the cat, but he's not going to get "well". Tough break for the cat who wound up in a high-risk lifestyle.