Ketones are produced when the body starts to break down fat to use as fuel. This occurs when there is too little insulin for the amount of glucose in the body....the body is supposed to use glucose for energy, but without enough insulin, the glucose stays in the bloodstream instead of "feeding" the cells, so the body finds a way to "feed" itself.
As fat continues to be used, ketones continue to rise and can result in a condition called Diabetic Ketoacidosis, or DKA. DKA is very serious and very expensive to treat (and not always successfully), so it's best to catch ketones early, when it's still possible to flush them from the body and get them under control.
The recipe for DKA is "too little insulin+infection/inflammation+not enough food"...with Mom-mom's bad tooth/teeth, infection/inflammation are quite possible which adds to my concern. Her high numbers are another risk factor.
It's important to test ALL diabetics for ketones, but it's especially important when they're in those high numbers like she's been lately.
If she starts to look or act sick, it's vital that you get a ketone test in immediately (other than routine testing)...if she has more than a trace, she will need to go to a vet that can monitor 24 hours.
DKA is deadly, so we want to try to prevent it or at least catch it early when it's more likely to be treatable.