| If you stand back from looking at everything through diabetes glasses, it's easy to see why the doctor said this. This doctor was likely working on a differential diagnosis. S/he may have even been suggesting that the pt was taking illegal drugs!
As you know, hyperglycemia can "easily" be induced in normal, otherwise formerly healthy people for other reasons, including steroids, infection, certain combinations of medications or "supplements", and even stress response from severe injury. For the doctor to conclude diabetes just from a chem or metabolic panel would be premature.
Some illegal substances will create a short-term hyperglycemia that presents itself with the symptoms of diabetes, but only for a short time. | 
