At the risk of sounding foolish, and maybe I'm missing something here, but couldn't there be something unforeseen that could possibly raise blood sugar that high in a non-diabetic? I know it'd be incredibly rare, but it doesn't seem impossible to me.
I can remember testing a family member and their blood sugar was 178 and they absolutely do not have diabetes (he went in and did all the tests of course to disprove). But a sugar like that seems like it'd be possible at least occasionally anyhow.
Please educate me.
