Low Glucose

[Adies]

I am 72, have pre-diabetes and in an effort to keep it in check, I am using a Freestyle Libre monitor. I find I regularly go in to the red (low) especially in the early morning and just lately in the evening. For tonight's Dinner at 18.00, I had Chicken Kieve, chips and veg. and here I am at 21.30 with a reading of 3.4 mmol/L. Often in the mornings, it is off the scale (under 3). Is this normal?

 

[Bruce Stephens]

Often in the mornings, it is off the scale (under 3). Is this normal?

No, though it's not that unusual for Libre sensors to give results that are just wrong (usually too low) so before panicking it's worth confirming some of the results with test strips (if you haven't already) just to see if it's a malfunctioning sensor.

It's also possible to get low results if you're sleeping on the sensor.

See https://forum.diabetes.org.uk/boards/threads/cgm-limitations-and-precautions.108188/

 

[Inka]

I am 72, have pre-diabetes and in an effort to keep it in check, I am using a Freestyle Libre monitor. I find I regularly go in to the red (low) especially in the early morning and just lately in the evening. For tonight's Dinner at 18.00, I had Chicken Kieve, chips and veg. and here I am at 21.30 with a reading of 3.4 mmol/L. Often in the mornings, it is off the scale (under 3). Is this normal?

Did you go up high before dropping down? Sometimes people will go high after a meal, stay too high for a while and then their insulin finally kicks in but overdoes things a bit, leading to them dropping a little low.

As Bruce says, it would also be worth confirming these results with a fingerprick test, especially the nighttime ones.

 

[rebrascora]

Libre generally reads a about 1mmol lower than actual Blood glucose for me, so a 3.8 is actually nearer 4.8. Also, if you lean heavily or lie on the sensor, it will cause what is called a compression low, when the Libre will falsely show your levels dropping, often into hypo territory (below 4) and then when the pressure is released it will gradually return to it's actual level.
They can also go wrong, particularly if you catch them and cause it to be pulled or lifted a bit, often by clothing or reaching into cupboards or on door frames and in those situations, if the filament has been disturbed, then it will usually gradually read lower and lower, until it tells you there is a sensor error and to replace.

Libre is a great bit of technology but you have to understand it's limitations and double check any readings that don't make sense with a finger prick, which is a more reliable indication of your Blood glucose levels.

I will link t a list of the limitations below...

CGM limitations and precautions

Moderator Note: This helpful reply was copied from another thread as it details some of the commonly experienced limitations of continuous glucose sensors. My blood sugar has been in perfect range for days now, but although I haven't changed anything, I'm starting to get very short periods of...

forum.diabetes.org.uk

 

[Leadinglights]

Many people who are in the prediabetic zone would not be using a Libre so you are getting a lot more information and perhaps that is concerning you more than it needs to as your body is behaving normally.
Without the Libre you would be unaware of what was going on between finger prick testing, people would often test before they eat and then after 2 hours and use the information from those numbers to modify their meals rather than what is happening next morning though than gives in indication of progress day to day, week to week etc.
You noted what your reading was three and a half hours after eating but what was it after only 2 hours.
You did have quite a high carb meal so your pancreas may have been kicked into action and overproduced insulin to then reduce your level down to a normal level.
People using finger prick will use the criteria 4-7mmol/l fasting and before meals and no more than 8-8.5mmol/l 2 hours post meal.

 

[trophywench]

And especially if it was a garlic butter Kiev, quite a lot of fat in both that and the chips - pizza effect.