I've started doing my own urinalysis on my cats with UA strips. And there have been a few that had ketones show up just slightly or a little more. But glucose was negative. I don't know how to interpret these results given no glucose present. Can somebody tell me what this means so I know if there's something I need to be treating?
Sometimes the color of urine can make some of the values a false positive. I've seen this with ketones and bilirubin.
I don't find the strips useful when it comes to finding infection (the white blood cell value often gives me false negatives/false positives), any true concerns should be checked under a microscope.
If you have any diabetic signs such as excess drinking/peeing, walking on their hocks, loss of appetite along with weight loss or cystitis/urinary tract infection (UTI's are very rare in cats) such as peeing around the house, crying at the litterbox, straining. That would deem a vet visit.
According to http://www.petmd.com/cat/conditions/endocrine/c_ct_diabetes_with_ketoacidosis, ketones are an emergency; you should go to your vet immediately.
However... if it's only a slight amount, and there are no other symptoms, I think just a call to the vet will suffice.
In either case, I suggest you ask your vet for some guidelines about what to do in future. The advice will probably be specific to your cat and the history of his diabetes management, and what readings are typical for your cat.
Results like these can mean any number of things but only a trained veterinary professional will be able to give you a correct diagnosis. It is good that you are attempting to take a more proactive stance in your pets health but this is a concern that only your veterinarian should answer.
I personally wouldn't want you to make the judgement call without consulting with an emergency veterinary clinic if off hours or with your own day clinic veterinarian. That is a lot for an individual to take on. I think it is best to involve you and a vet in the decision of your pets health. Both you and the vet want what is best to treat the animal or end the suffering in a humane way.
As a pet owner having all the numbers and knowing where your vet hospital/ emergency clinic is before an accident actually happens is critical. The earlier the emergency is caught the better. Always have a plan! :)
I found a website that ran down the analysis on what everything meant on the urinalysis strips. It said that ketones are substances formed in the body during the breakdown of lipids, or fat. This might explain their presence as most of my cats eat much less in the summer because of the heat. I'm in Texas and we're having 100 degree days. So the cats eat less and their body starts to breakdown fat for fuel, therefore ketones show up during testing. I suppose it's just a theory but I hope I'm at least on the right track for an answer.