The thing is something is not right so keep the vet at it, they should be looking for something else.

Cushing disease would have shown up in his blood tests though.

What showed in the blood test will depend what they were looking for, it may just have been a basic screening. Perhaps you can ask the vet what the blood test was for and what it has ruled out, often it is just infection.

Well I know much less than any of the above but if you take the human scenario. When the blood is sent away they label asks for specific test (or tests) to be done. So when you go back to your Doc. and (s)he says all is OK you really need to ask for further tests with an instruction to look for less common ailments. Same applies to your vet. probe a bit more, be firm (but polite) and make sure they realise it's a definite and sudden change in his behaviour.

As Pita said I would assume that they only ran a general screen?

To test for Cushings, a blood sample needs to be taken, and the animal is then injected with a synthetic ACTH hormone. A second blood sample is then taken one hour post injection.

I see no they havent done the test then. Its difficult to have faith in a vet that was so young -he looked 12! (obviously im getting old!)
Maybe i should try different vets they told me to limit his water which didnt impress me.
Weve just had another very wet night. Is cushings treatable?

Cushings is treatable with medication, and most dogs cope well once they are stabilised. It can be an expensive condition to manage, and blood test will need to be taken at regular intervals - how often will depend on the level on control, but usually every 3 - 6 months, although this may be more regular to start with.

It's really no good seeing a vet who you don't have faith in, perhaps it would be worth going for a second opinion elsewhere if your vet is reluctant to perform further tests? Or of course if you are unhappy.

Time to try a different vet, but find out what the first blood test has ruled out first.

They should give you a copy of the results if you ask and a new vet will contact them anyway to see what work they have already done, well a new vet should.

Hi VL if diabetes/kidneys/cushings have been ruled out other things to consider in an older dog are prostate problems and CCD (canine cognitive dysfunction) maybe even a little of both.

You say Frosty is 'losing his marbles a bit' , in what way?

CCD is like Alzheimer's in humans,it has a variety of symptoms including increased thirst and urination and sometimes grumpiness because the dog gets confused, it responds well to medication