What Tests Are Done To Detect If Someone Has Diabetes Before That Person Starts Showing Symptoms Of It?

What tests are done to detect if someone has diabetes before that person starts showing symptoms of it?

Is It Possible To Have High Blood Sugar/ Diabetes That Is Not Recognized By Standard Tests?

I am obese, but have never had diabetes or pre-diabetic conditions. I had a baby in 2008, but did not even have gestational diabetes. However I remember something I read which mentioned (just a vague memory here…) that it’s possible to have some gestational diabetes which is not detected by the standard glucose-measuring [...]