Forgive my ignorance but, isn't a finger prick measuring real blood glucose? Or are you referring to a more long term/average a1c? (Or is there something in between that I just don't know about?)
"Real" blood glucose is glucose as measured by a reference standard device, like the YSI 2500, arterial blood gas machine etc. Finger pricks are accurate to within ~15% of the real blood sugar, and reference machines like the YSI are accurate to within ~1%.
Exactly. And I doubt that this device is used in any lab, except in a clinical lab setting. I have seen it in clinical trials. Focus on the word "arterial blood", this gives you an idea. :-)
Sure, it's a very bulky device and expensive to run! But, when you're talking about 'real' blood glucose, it's the gold standard that you need to use to pass regulatory scrutiny.