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Advice sought with my control

PJR76

Member
I've recently started with the FreeStyle Libre monitor and am struggling at the moment to get my glucose levels into the "normal" area.

I'm aware of the c.10 minute delay between the FreeStyle Libre (interstitial) and the tests taken via a lancet (capillary).

I'm not currently 100% convinced with the accuracy of the FreeStyle Libre taking into consideration that the upper readings (hyperglycemia) appear to be approximately 4 mmol/L higher than capillary readings.

I put my first sensor on on the 14th May, so it's still early days.

 
Hello, @PJR76 , and welcome to the forum!

Could you fill out your details in your profile, especially type of diabetes and medication? No-one can say anything sensible about your question without knowing how you manage your diabetes now.
 
A few things I have learnt about the Libre through personal experience
- the Libre is most accurate in the 4 to 8mmol/l range.
- the Libre does not like rapidly changing BG such as when eating or exercising
- the Libre is factory calibrated. Not every person is the same as the generic factory person. I am not. However, I have found that open source apps (such as Glimp) use different algorithm to the official app which allows calibration against finger prick readings
- some Libre sensors are just off. Abbot replace these free of charge
- the value of the Libre is in the trends rather than actual values
 
PJR76 said:
Where can my profile be found in which to enter in my details? Is there a URL?
Click to expand...
I'll put my info here for the time being until I can locate the proper place.

Type 1 Diabetes Mellitus (diagnosis 1993)

Bolus: Humalog
00:00 to 18:00 Ratio: 2.25u per 10g
18:00 to 00:00 Ratio: 2.5u per 10g

Basal: Tresiba
28 units c. 9pm

Correction dose sensitivity (Humalog):
00:00 to 18:00 Ratio: 1u per mmol/L
18:00 to 00:00 Ratio: 1.2u per mmol/L

I think my most recent HbA1c was about 84 mmol/mol

If you need anything else, just shout.
 
PJR76 said:
Where can my profile be found in which to enter in my details? Is there a URL?
Click to expand...

Assuming you are using your browser, as opposed to the app, hover. On your user name in the top, right of the screen, and go to Account. You can do it from there.

If you are using the App, you really need to log into the browser option. Although small, it does work on phones and tablets.
 
Hi, @PJR76 , the persistent rises several hours after food/bolus are suggesting that maybe basal is too low - I'd maybe try a basal test: wait till about 6 hrs after your last meal/bolus so they have worn off, then just watch and wait for 8 hrs without carbs or bolus and see if the level stays steady or not. If it goes up by more than 1.5 or so, that's a strong indicator that basal is too low as it should hold you more or less steady. It can be nudged up in 10% increments but wait for 3 or so days to see how that plays out before increasing again.

Also, I'm wondering if you're pre-bolusing, injecting about 20 mins before a meal? It gives the insulin time to get to work and can make a major difference in minimising post-meal spikes.

Another candidate is over-treating lows. It's very easy to do, have done it myself far too many times, but one of the early things I learned from libre was that if bg was trending down, no, it doesn't need a Mars bar or a half bottle of lucozade, very often a couple of dextrotabs is enough.

Sugar Surfing by Stephen Ponder discusses these sort of things at length and how to "read" libre and cgm graphs - it helped me a lot when I started out with it.

Another thing which helped was "blinging " libre up by attaching a reusable transmitter called MiaoMiao to it, it then reads libre every 5 mins and sends it to an android app xDrip+, so you get a full on cgm graph, you can input bg readings to tighten up accuracy, and set hypo and hyper alerts.

The hyper alerts really make a difference. I've got mine set to 7.6 and 8.5, so if my last meal/bolus calcs didn't work out, I'm going to get woken up, can then make a judgment call on whether another unit or two is needed, so I can avoid waking up to numbers in the teens.


Here's links to the gizmos if you're interested in that route:

www.miaomiao.cool

https://jamorham.github.io/

By the way, I see you've just joined, so welcome aboard!
 
Hi, @DunePlodder , not seen you round these parts for a while!

Don't want to derail the op's thread, but I've got a vague recollection that you're looping, so thought I'd take the opportunity to mention that during the T1D Rise of the Machines Scotland seminar here in rainy Edinburgh yesterday, Dana Lewis mentioned her new book, Automated Insulin Delivery, well worth a look for loopers.

https://www.amazon.co.uk/Automated-...very&qid=1558193930&s=gateway&sr=8-1-fkmrnull
 

No Scott, I'm not looping yet, though I've done a bit of Open Looping with AndroidAPS.
I have the t:slim X2 which hopefully will close the loop next year. In the meantime there is Basal-IQ to look forward to.
That will be an interesting read, thank you.
 
Hi Scott,

Thank you very much for your lengthy and detailed response.

There are quite a few responses which I feel you have probably hit the mark.

I have decided that the basal could well be a little low, so have indeed decided to increase it this evening by 2 units. One of the characteristics of Tresiba is that it takes roughly 3 days for any evidence of changes to show. I assume that must be due to the chemical makeup of the insulin itself. I however do feel that with Tresiba, with my body anyway, it can tail off sooner than 24 hours.

I do generally tend to inject my bolus injections after my meals (which incidentally is habitual), so that could well contribute to the higher than normal readings. Where possible I'll try and inject before meals, but my lifestyle may not allow for 20 minutes. Humalog I believe has been designed for "non-compliant" diabetics and is usually pretty forgiving.

The period where I was hypoglycaemic for roughly 2.5 hours, I probably did over correct. I'm still not sure what caused me to go hypoglycaemic in the first place on that occasion. I do sometimes find it difficult to accurately calculate carbohydrate portions, so I may have drastically overestimated on that occasion. I think I injested roughly 100g of carbs without bolus, so I suppose I was asking for trouble.

Hyper alerts will be invaluable to me, probably also hypo alerts too; so I'll definitely be checking out the attachments assuming they are easy to use.

I have a lot of research to do, so thanks for your advice.

Philip
 
PJR76 said:
I have a lot of research to do, so thanks for your advice.

Philip
Click to expand...

No probs, Philip!

If it's any comfort, I started using libre about 3 yrs ago and was seeing the same sort of graphs you're seeing - it was a bit scary seeing that much detail!

But the more I used it, the more I started seeing things which bg strip tests weren't telling me, and I started looking at the problem areas and figuring out solutions for them.

It takes a while, this stuff doesn't happen overnight, but the graphs started getting flatter and flatter because I could see what x carbs and y insulin do.

Three years into it now, I'm much more confident in making a bolus call, but, as you know, it's T1 so will throw a flier every now and then!
 
I was wondering whether you do a finger prick test for your highs and your lows so you can confirm if you're actually running high or low. sometimes the libre isn't accurate when it's out of the 4-7mmol/l range. I had a situation where my libre said I was 13.5, I was going to correct but I did a finger prick test which said I was 9.5. If I didn't do a finger prick test to confirm, I would have entered hypo land.

I have to agree with Tresiba is not quite there for 24hours, so I inject on time every day and yes do give it that 3-4 days window. Also consider the basal testing, so you can judge whether you have enough basal on board. I know over treating lows is quite common, I do it too, do you give it 15 mins? and then re test to see whether you need more carbs or none.
 
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