Theer are a few tests that can determine if you are really borderline( and yes I use that term because its accurate).
The test involves one week without any type of medication.
You are placed in the hospital on teh last day fo the week with no meds.
Then the following morning you are given a fasting glucose test, then a 30 minute load with a 30, 45 and 2 hour pull, again allw ith no medication. At teh same time they are also doing an insulin level test. This given them a clue as to how much insulin you are producing.
It also gives them a clue as to how much glycogen your body excreted.
This series of tests is definitive if suspect borderline is too controlled and static.

Any diabetic has periods of highs and lows regardless of the effectivness of the medication.

Joslin diabetes Center has office in almost every region. They willd o a rescreening as well.