Re: How were you at diagnosis?
@Louise:
My blood sugar levels had been slowly rising ever since I was diagnosed, and the number of tablets I was on was also increasing, so I asked my GP to refer me to the proper diabetic clinic with consultants at the hospital, so I could see a dietician and get tips about how to keep the blood sugar lower. The consultant immediately said I was very young to have type 2 diabetes (he said he would get anyone under the age of 40 with diabetes tested for type 1 because that was more likely than it being type 2), and was not in a high risk group for type 2 diabetes, and gave me a blood test form for tests for type 1 (I left it for a few months until the next hba1c was due to actually get the blood test done, I could not face having an extra blood test, they really scare me).
The tests came back positive. This was a bit of a shock because days before the I had the test results back my GP changed me from pioglitazone to gliclazide (in addition to metformin), the gliclazide worked wonderfully and I felt better than I had done for ages, so I assumed this meant it must be type 2. The consultant said the reason it had worked because when you get type 1 in adulthood the cells take quite a while to all die, so the tablets make the remaining ones work harder to produce insulin (and help kill them off in the process).
There are three blood tests they can do to test for type 1 diabetes - one for GAD antibodies, one for c-peptide levels, and another one that I don't remember. I had the first two done, they were both positive for type 1 diabetes. If you look on wikipeadia, it has an explanation of what each one is testing for.
tl;dr: they realised when the blood test for type 1 came back positive.