Hi Jow,
I'm in no way an expert on this sort of thing

but just wanted to give you my experiences.
I had a fasting blood test towards the end of last year which also came back normal, even though I personally believe that I am definitely insulin resistant, or certainly have blood sugar issues, as if I don't eat for a longish period of time I get very shaky, irritable and sometimes get migraines.
My Dad is diabetic (type 1 I think as he has had it since his 20s), and he has always said that if you are diabetic you shouldn't have fasting blood tests as they can be dangerous! I know that's not completely relevant to your question, but I wanted to mention it as I was concerned by the idea of you having fasting blood tests if you have been diagnosed as diabetic.
Hope this helps a bit, and I'll be interested to read anyone elses's replies too!
CW