Hi Laura,
not completely sure of how much keytones, but would assume it would be more for high keytones over a long period of time which would cause problems. Think keytones now and again coupled with what you experienced (not being well) is power for the course,(Its your bodys way of telling you something is wrong) where as if you weren't looking after yourself ie, not injecting and eating wrong diet then you would have complications including keytones,weight lose,ect, (similar to what probably led you to diagnosis) I only test Andrew for keytones when he's feeling poorly, or has had high readings over a 6hr period.
Hope this has helped in some way, though i'm no expert.
take care
Suzi x