Good call, Sjay!
Sounds like you've picked quite a good food for Oliver. Switching from dry, high carb food to healthier high protein wet food can have a dramatic lowering effect on blood glucose levels - and in a
very short space of time. The very positive changes you describe in Oliver's clinical signs certainly point to his blood glucose having lowered significantly: they are typical of a cat recovering from hyperglycaemia.
The only way to determine whether or not Oliver may still need insulin is to test his blood glucose levels. I see that other members have already given you some information about this.
Testing is a pretty straightforward process. After maybe a few hiccups when you first start, it soon becomes second nature. Here are some forum guides so that you can start learning what's involved (includes helpful videos).
Home Testing Links and Tips (includes how-to videos)
Tips on Testing and Giving Injections (really good diagram of where to test on the ear at the beginning of this thread)
You mentioned above that Oliver has tested positive for ketones at some stage. All diabetics need to check for ketones periodically but in a cat who has tested positive it's important to monitor more closely. It's a very straightforward thing to do. Just pick up some ketone test strips from a pharmacy (or other place that sells diabetic supplies) and test Oliver's urine with the strip. NB - anything more than TRACE ketones needs veterinary treatment, so if you get a any higher a result than Trace you need to take Oliver to the vets straight away. (If ketones aren't treated promptly a cat can develop diabetic ketoacidosis - potentially life-threatening and expensive to treat.)
I'd strongly recommend you let your vet know straight away about the big improvement in Oliver's clinical signs so that you can both review his treatment strategy. Again because Oliver has tested positive for ketones a little extra care is needed in terms of managing his insulin requirements. Whereas it might be relatively low-risk to take a 'wait and see' approach to making a decision about whether to commence insulin treatment in a cat not prone to ketones, a more cautious approach is wiser in the case of a ketone-prone cat since insufficient insulin can result in ketones reappearing. The dose that your vet will have prescribed is highly, highly likely to be
way too high for Oliver's needs now that he has made the diet transition. You were completely correct to withhold the insulin. However, his better blood glucose levels now need to be assessed. In light of those results you and your vet will be able to determine whether Oliver's pancreas may still need a little support from insulin but at a much-reduced dose than the one set by your vet at time of prescription. Feel free to ask for advice and opinions here at any time. There are members here with a wealth of experience in the treatment and management of feline diabetes.
Food-wise, it's good to hear that tuna juice is helping you to tempt Oliver away from the 'dark side'!

Which Fancy Feast flavours are you feeding? I believe the Classic patés are good choices. (The Gravy Lovers range are too high in carbs for general feeding but good for a hypo kit.)
Again,
great call on the insulin.
Mogs
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