Blood sugar trend question

I have had my CGM for 2 weeks now. My first 10 days were amazing. My numbers showed very good control 80s-150s post prandial. I spot checked with my glucometer to verify numbers since a CGM is new to me. My trend never showed any big spikes after a meal. My baseline stayed around 100s. I changed my CGM last Thursday and my numbers started going much higher. I verified with glucometer and they were accurate. I am seeing regular spikes to 180s-200s with my baseline around 130s. About an hour after I eat I see a mountain on my reader trend. It goes up sharply which was not happening previously. The only other thing different is that I had to change my Treciba pen last Wednesday and my Fiasp pen last Thursday. I went up on my Treciba from 52 units to 60 units. It does not seem to make a difference.

Is it possible that there is something wrong with the insulin pen? I have not changed my eating habits, at all. This just seems weird to me. The Treciba pen is from a new box I picked up from pharmacy.

I am putting this out there because this community knows more than most medical people, You folks live it and I am still learning. Ideas? Suggestions?

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It’s rarer but it definitely happens. I think I’ve had 2 pens I’ve had bad results over 2 years? It just depends what it’s been exposed to. Maybe it was on the outer edge of a box shipped and got exposed to heat.

I change my Omnipod pod first and then if the second pod gets bad results too I change the pen.

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Welcome @SusanS.

I agree with @Marie20. Something could have cooked the pens. You did not share anything about general area where you live or if you work and carry the pens in work cloths in a hot environment. A hot environment can ‘toast’ pens and pumps if the ambient temp is greater than about 90F.

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I keep my pens in the refrigerator. I only take my Fiasp with me to work and I bought a Frio Insulin Cooler Wallet to keep it in. That keep the pens cool to a max temperature of 78.8 degrees, even if it’s 100 degrees outside. And that stays in my insulated lunch bag. I do not think it’s a sensor issue because the numbers do correlate with my glucometer. Maybe I should switch to a different box of pens to see what happens

You sound like you have a good plan. Switch boxes. If you get your pens locally, ask if they are temp controlled over as much of the delivery route as is known & compare to local temp if high heat. If mail order, do they arrive on cold packs that are still cold.

If the pens become suspect, check out completing an FDA MedWatch report. There may be something there to report.

Its a 30 - 50 point increase post-meal?

Its most likely not the pen, although its possible. It could also be difficulty with absorption at the injection site, or many other variables. I would swap sites first.

Normally yes, 30-50 points but now I’m starting out 30-50 points higher at baseline (140s) and going up to 200s with no change in diet.

I don’t find that magnitude of shift very uncommon, for me. It may be for you.

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It could be the insulin. It could be meal choices. Are you eating something different? Is your pre-bolus staying the same or has that shortened? Not sure if you have had the system long enough to notice whether your monthly cycle might come into play here? I found 2 weeks before, I’d run low and when I started I’d run high.
And than of course my favorite answer is no reason at all. Can’t tell how often that comes into play when dealing with diabetes. Sometimes there is no answer. Those times, I just correct and move on. So unfortunate that diabetes doesn’t always play by the rules.


I’ve found with Tresiba, if I were to adjust the dose, it would take about 3 days of the new dose to see results.

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I have not changed eating habits at all. I am staying in a hotel room for the past 12 weeks and buy the exact same things all the time. I don’t have to worry about a monthly cycle…the only good thing about menopause :slight_smile: I am not sure what you are asking with “Is your pre-bolus staying the same or has that shortened?” Can you explain?

Sorry I have been offline for awhile. Trying to reduce stress levels and find turning tech off is a great way to reduce my stress levels. Especially now with news being all bad.
I find, remember this is my experience, most of any post meal rise is usually because my timing on when I took my insulin versus when I ate would make or break my post meal numbers. Most times 15-20 minutes works for me. Of course the higher the blood sugar before eating and how much carb and protein will also change the timing. There are many books and online resources that talk about this. But I found once I got a CGM and saw what was happening post meals, I saw how much timing matters. Good luck and if you need some of those resources, let us know.


While this may be more of a guy thing, I often see a phenomenon that might be called “new gadget syndrome”. For the first couple of weeks, things are super because I’m more attentive than usual, checking and double checking, etc. Then, gradually, I just bet a bit more complacent … not consciously … but things just aren’t quite as sharp as they first were. Of course, that new steady-state if often better than the old steady state, but just not as spectacular as that first week or two.

You, of course, may be more disciplined than I.

Stay safe.