Hi Erin
I am not a doctor or nurse. But on an occasion when I had really high BG and ketones (This unfortunately happens to me at the slightest infection/illness ) I was asked this by my diabetic nurse, she specifically said to me you haven’t used a needle twice or forgotten to clean with a wipe first ? I know some people can do this for years without any problems at all, this was aimed at me as I seem to be prone to infections easily. However it makes me think it might be possible for some people. Hope that helps, don’t know how you would tell though. We never really found out why I was feeling ill high BG and ketones for a couple of days on that occasion, obviously I was fighting off something, I remember I did have a nasty cut on my hand at the time (which was suggested as possibility) but I will never know for sure.