Like
@rebrascora, I have only tested ketones for a persistent high BG. I con't consciously think about whether I feel unwell but it is rare for me to be persistently that high and not feel unwell.
The reason for the ketone testing is the risk of DKA. As I understand it (but I am not medically trained), this is not a risk for a short high spike.
Regarding low BG alarm, there are two trains of thoughts
- have low alarm high enough to get an advanced warning to avoid hypos - you can treat before they happen
- have low alarm low enough to avoid alarm fatigue.
Obviously, these can contradict each other and are personal approaches.
As with many things diabetes related, there is no one answer - you need to work out what is best for you.
Personally, I favour the lower level (but still not hypo) because I have suffered from alarm fatigue and started to just ignore it which isn't good.
So, do not feel you need to set it at 5.0 because some on the forum does this or set it at 3.9 because your DSN tells you to. Try different levels and see what works for you.
My only caveat is that a hypo is anything under 4.0 so I would set it no lower than that - you don't want your body to get used to being hypo and lose hypo awareness.