Herb, that glucose tolerance test is a glucose challenge to see how your system reacts to a very high sugary drink, blood levels are taken at fasting stage then 1 hour after the drink, then the second hour and so on, i mentioned insulin as well because it's good to know how much of the hormone your pancreas is releasing when under a real hard challenge as well.
Normal fasting glucose tests do not show how your system reacts when under pressure only what it has come back to over night.
It's great your treating yourself like a prediabetic, possibly saving yourself from further nerve damage, has the good diet and ALA brought your levels back to normal levels again ?

Brian