Type 1 Unexpected blood glucose

tonilmackay said:

Hi everyone,
I went to sleep last night with ok blood sugars at 7.5 and woke up this morning to it having jumped up to 20.0. I have no idea why this would be as I had done everything the same as always, and my sugars are normally steady overnight. Can anyone suggest why this might have happened? Feeling a bit lost.
Thanks!

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Hi, welcome to the forum. But this could be a whole host of reasons. Are you type 1 or 2? I assume 1 given the levels, but I could be wrong. Without knowing your complete history for the day, including medication, what you ate/when you ate, BS levels etc., it is very difficult for anyone to tell you what could have happened.

It could be any or a combination of some of the following:
Insulin went off (Basal or bolus)
Insufficient insulin or medication, may have been raising as you went to bed (won't really know without a CGM)
Assuming injections (injection sites and lipohypertrophy)
You had a large meal late, or too close to going to bed
You had a high fat or protein meal and that raised levels overnight
Combination of above and dawn phenomena
Stress or lack of sleep
Dehydration

And a whole host of other reasons.

I would say the most likely is that you forgot your basal, or that you have come down with an illness, so your blood sugar is basically out of control and has hit the "20 limit". That's the point where the kidneys start removing the excess glucose so no matter how much excess sugar you have your BG sort of won't go higher.

helensaramay said:

Unfortunately, food is not the only thing that impacts BG and even the impact of food can vary over time.
@Muneeb has listed most of the obvious candidates for the unusual reading.
The only one I would add is that your reading of 20.0 could be wrong.
Did you wash your hands and try again? You could have had something on your fingers before the test.

It is probably too late to do anything now but the tip is always:

"If your reading is not what you expect, wash your hands and try again."
​

If you are using a CGM or Libre and have unexpected readings, check it with a finger prick.

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An unexpectedly high morning reading could also be caused by an overnight low... Look into symoji effect. When checking basal rates you really need to check every few hours during the night. A PITA, but well worth the investment

helensaramay said:

The only one I would add is that your reading of 20.0 could be wrong.

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Although this is possible (and DO double-check before you treat), if your number is 18-21 in my experience it's probably because your BG has hit the "20 limit". When my hands have sugars on them I generally get a random number like 26 (or "HI").