Thanks for the tag
@Bron and Sheba (GA) and sorry about the delayed reply, I didn't even log in yesterday. The good side of that (for me) is I read this to the end and things are looking much better.
You have all my sympathy with the ketone situation, it's terrifying once a) you've been through it and b) fully understand the implications. I feel that getting the blood ketones are a double-edged sword - it's great to have those readings so early that you can take action, but on the other hand you start worrying a lot earlier when you see the numbers going up. One of the things I like to do to calm myself when I see an increasing blood ketone is to also get a urine ketone reading because (for Minnie at least) what I think is a worryingly high blood ketone reading doesn't even show up on the urine reading. I've just looked back and on 29March just in the middle of her ICU-cation (3 times in/out - 'she's fine to be at home' followed by re-admitting within 2 days) her blood ketone showed 5.9 and urine was still 'trace'. Now, knowing that doesn't stop me taking action or worrying, but it's like having an advance warning like the yellow gas tank warning light in the car.
It's great you can give fluids, I haven't had to do that yet - I was all ready to do it but she ended up in the hospital, way back in the spring. And great that you gave the insulin, too! Has the vet talked to you about giving Regular insulin for when the ketones are high? Our IM introduced me to it this last go-round - her advice when ketones are increasing is fluids, feeding and continue with the insulin (even if not eating). And when she's got increasing ketones and 'high' BG I will give R insulin. I put "high" in quotes because you have to work out the right dose of regular insulin for your cat and it's a trial and error effort, not to be carried out without supervision. Reading your latest update though, seems that you are doing great without the supplemental R.
Oh, the urine culture. I've had to wait for that too. I'm not entirely sure how much is due to the lab communication and how much is because they have to wait for the culture to grow. Last time round, they took a sample on Tues for in-house culture and Sat morning I hadn't heard back and she was in/out of the tray again so I called them. Confirmed a UTI, but they wanted to send it out for another culture to identify the exact bacteria and that was yet another week...but, we got the right antibiotic which cleared things up (though it was 10 unpleasant days injecting her with a stinging antibiotic! I had to bring in a second pair of hands and a serious kitty burrito to do that).
Sorry for the rambling, thought it might be comforting to hear someone else's inner voice who has a ketone-prone kitty. I have a column on my s/s for ketones - way over on the right. I have lots of columns, you'll notice...
AND, to end on a positive and hopefully encouraging note for you - Minnie's ketones have been fine for ages. Her blood ketone has never been lower than 0.2 - for her she is typically in the 0.3 - 0.5 range.
Good luck, I'll look out for you - feel free to tag me if you need moral support or have questions on my experiences!
Now that she has the insulin and fluids in her, we will monitor, and make sure she is eating as well as possible (bed side food service while being petted, which is her favourite way to be pampered, is available 24 hours a day! She knows she has us under her thumb, lol).
Mine do! 
