There is an interesting debate at http://www.diabetesincontrol.com/index.php?option=com_content&view=article&id=9375&catid=53&Itemid=8 . Please visit.
I think that often we, and our docs, pay too much attention to lab tests. They are valuable tools, I’m sure, but many of the studies relating bg and A1C point out that while there is a relationship that the A1C still has an enormous amount of scatter. And even in the diabetes community the recommendations for A1C’s are often hopelessly ridiculously out of whack with reality - e.g. Bernstein’s goal A1C of 4.2%, which is below 99% of the non-diabetic population.
I might be in the minority here (being an old timer), but I was diagnosed without a blood test at all. Now not every case of diabetes is as obvious as a 14 year old kid in DKA coma with every single symptom of DKA. But docs really can and should do more than just look at lab test results in coming up with diagnosis and treatment.