Gp. When i was first diagnosed, they told me anyhting below three is low, anyhting above seven is high.
I'm not sure I'd go along with those figures, which are a bit lacking in context. For a start, they're referring to one-off fingerprick readings where you may not be able to establish exactly why your BG is where it is. BG will vary with the amount of carb recently eaten, but also following liver activity making new glucose which can be triggered by many things.
I would agree that readings below 3 mmol/l are low. However, for myself, I would regard any reading below 4 mmol/l as being low. That doesn't necessarily mean that I need to do anything, and I regularly have readings around 4.6/4.7 mmol/l which are steady - ie they're not on the way further down.
I'd disagree though that any reading above 7.0 mmol/l is "high" - mainly because of lack of context. Because of the inaccuracy of fingerprick testing, a true BG value in the low sixes could easily generate a result of over 7. And it doesn't explain or take into account what's been going on - so exercise (for one example) could easily raise BG in the short term, as can stress - all from liver action.
And if you've eaten any carb, and test 45 minutes afterwards, you are likely to see relatively elevated levels - the example I keep quoting is of a small latte taking me from 5ish to 9.6 mmol/l in 45 minutes - a perfectly normal and to be expected rise.
The real question is not so much how high your levels go, but how quickly and effectively your system works to lower them. That's why the recommendation usually is to test right before eating as a baseline, and then two hours later - not to see how high you go, but to see if you've returned your BG to baseline or close enough. The problem for those of us with T2 is that levels once elevated tend to stay higher for much longer than they should.
