@Suzanne & Darcy , I had an issue today. I accidentally left the insulin out last night from 9pm to 9am! Our house is cool, high 60's, and it wasn't in the sun. Looking at it, it looked fine. Not stringy or clumpy, etc. I decided to give to Jenny then test +6 to ensure it worked ok. PMPS at 9am was 341. +6 was 327, hardly any change! She has consistently been in the 100's at +6, so she hardly moved down at all. If you look at her spreadsheet, it was definitely an aberration.
So I called the vet to get a new bottle of insulin today. Jenny has a 3 month checkup next week where we would get a new bottle anyway. The vet was not wanting to do it, said the 327 could be some other reason, keep using the old bottle. The vet told me 3 weeks ago to go from 1.5 to 2.5, but instead I started stepping Jenny up to 1.75, then 2.0, and was going to 2.25 today (but delayed due to this). The vet said it's because I didn't take her directly from 1.5 to 2.5 and I need to go to 2.5 immediately. I told her the last time she had me to go up a full unit, Jenny went hypo the next day, so I have learned to step her up and not make big changes. Vet said fine, but take her to 2.5 now, that's why she's high today. I don't agree with any of that. Anyway, after 10 minutes of me politely arguing, she agreed to give me a new bottle today though she still said I don't need it, it's the dosage, just go to 2.5 using the old insulin.
I agree with the vet that 12 hours out in a cool house should not make the insulin go bad, but it sure looks like it did. Also I've been on this same bottle for 3 months. Anyhow, thoughts? I still plan to go to 2.25 and not 2.5, and will just have to deal with that at the vet next week I guess. I sent her my spreadsheet and a curve I did yesterday.