Freestyle Libre and accu chek aviva

[Elinmelyn1]

First ever post on a forum so bear with me!
I am on the accu check insite pump and today was given a Freestyle Libre sensor. Have been checking on both all evening and am finding inconsistencies already with readings. Last check on the sensor said I was 2.9, but when I did a finger prick check on my meter it was 7.3. Has anyone else found this with CGM’s?

 

[LooperCat]

Hi, and welcome! Tagging @daisy1 for some welcome blurb...

The sensors can be a bit flaky for the first 24 hours, as the flesh around them recovers from the insertion process - there’s inflammation and white blood cells sent to the area to heal the hole you’ve just made. I install mine 24 hours before activation, to let it all settle down a bit, and it’s accurate from day one, pretty much. Also, the more sensors you have, the more accurate they become, at least in my experience. I think your immune system learns to ignore the intrusion of the filament after a while.

 

[Scott-C]

Hi, @Elinmelyn1 , like @Mel dCP says, it's a good idea to apply the sensor but then delay activating it for about 12 to 24 hours or so to give body responses time to settle down.

When libre came out in Europe, users figured that out pretty quickly, so much so that when it was eventually licensed for use in America, they built in a 12 hour warm up period for exactly that reason, after learning from us Yoorpean guinea pigs, lol...

If it doesn't settle down after a day or so, don't hesitate to call their helpline, they're normally pretty good at replacing rogue sensors (avoid emails - they never reply to those).

One of the things which I'd encourage you to do is bg test more in the first week or two of using it. It gives you a clearer idea of how to understand the difference between blood glucose tests and interstitial fluid glucose scans from libre.

For example, I found that my sensors tend to run about 1 below blood, so if I got a scan saying 4, I'd reckon it was more likely 5.

Try to remember that these aren't perfect "plug and play" devices. They're extremely complicated devices operating in a hostile environment and sometimes they get it wrong.

You can get a lot out of them, but one of the skills in using them properly, which takes a few months and a few mistakes to acquire, is learning how to identify when they are right and when they are wrong.

Two good books which helped me a lot in this brave new cgm world, a couple of quid on kindle:

Sugar Surfing, by Stephen Ponder

Beyond Fingersticks, by William Lee Dubois

Good luck, like I say, any sort of cgm can go a bit sketchy at times, but once you figure out their quirks, they make a significant difference!

 

[EllieM]

I think your immune system learns to ignore the intrusion of the filament after a while.

Unfortunately some people's immune systems don't, and just get to dislike it more. . Hopefully the OP will be one of those in the former category, but there are some people for whom the libre does not work.

Last check on the sensor said I was 2.9, but when I did a finger prick check on my meter it was 7.3. Has anyone else found this with CGM’s?

Also bear in mind that the libre will lag behind your actual blood sugar by about 10 minutes. Hopefully the reader will be more accurate in 24 hours, but if not then you can phone Abbott and they will replace it (and give you a RTS envelope to return the dud one). I would be very very cautious about treating for hypos based on a libre reading alone, and indeed Abbott put in the following disclaimer
The FreeStyle LibreLink app and the FreeStyle Libre reader have similar but not identical features. A fingerprick test using a blood glucose meter is required during times of rapidly changing glucose levels when interstitial fluid glucose levels may not accurately reflect blood glucose levels or if hypoglycaemia or impending hypoglycaemia is reported by the LibreLink app or when symptoms do not match the FreeStyle LibreLink app readings.

 

[Deleted Account]

I would be very very cautious about treating for hypos based on a libre reading alone

I would not treat hypos or calculate a bolus based on Libre readings.
Even taking the delay into consideration, it is not accurate enough.

And on the topic of lows, bear in mind pressure can cause the sensor to read extra low. So, night time readings (when you may lie on it) may be wrong.

 

[EllieM]

I would not treat hypos or calculate a bolus based on Libre readings.
Even taking the delay into consideration, it is not accurate enough.

And on the topic of lows, bear in mind pressure can cause the sensor to read extra low. So, night time readings (when you may lie on it) may be wrong.

Well, I wouldn't either, because I'm one of those for whom it no longer gives useful results. But, interestingly, Abbott now claim in their literature that it's accurate enough for insulin dosing, so maybe it's just a vocal minority for whom the readings can be somewhat erratic? Presumably they've done at least one study which says it's accurate? There are a lot of users, and the ones for whom it works don't need to post on chatboards to ask questions about it.

 

[LooperCat]

Well, I wouldn't either, because I'm one of those for whom it no longer gives useful results. But, interestingly, Abbott now claim in their literature that it's accurate enough for insulin dosing, so maybe it's just a vocal minority for whom the readings can be somewhat erratic? Presumably they've done at least one study which says it's accurate? There are a lot of users, and the ones for whom it works don't need to post on chatboards to ask questions about it.

Once I established how a sensor is reading, I quite happily dose from it, even more so now I can blood calibrate it with the MiaoMiao Bluetooth transmitter I bought to sit on it.

 

[Scott-C]

Abbott now claim in their literature that it's accurate enough for insulin dosing,

Ellie, it's a difficult question with no easy answer.

Abbott are now working up their generation 2 version of libre, which is going to send (very primitive) hypo/hyper alerts to the reader.

As part of that, they've said that they are going to calibrate each one individually instead of en masse batch calibration.

I've certainly noticed over the last few months that reader scans are a bit tighter than they used to be. There's some speculation that they've already started doing the individual calibration as a test run for the version 2 roll out.

Dosing off it is one of these things which people need to make their own choices about. Took me a few months to get to that point. I've got fairly flexible working hours. I'd bg test about 9:30 am, got a sense of how close or not it was, then would generally eat about noon, so after a while of doing a noon bg test and finding it pretty close to what a scan was telling me, I decided the noon test was redundant, so was ok bolusing off the scan.

I'd rinse and repeat for the evening meal. Sometimes I'd bg test for it, sometimes not.

After using libre for a while, I think we pick up a sense of whether it's a "good" or "bad" sensor, and that's certainly played a big part in whether I'll bolus from it or not.

Doing the geeky stuff with blucon and xdrip adds a different layer of complexity to it, a story for another day...

 

[daisy1]

@Elinmelyn1
Hello and welcome to the Forum Here is the Basic Information we give to new members and I hope you will find it useful. Ask as many questions as you need and someone will be able to help.

BASIC INFORMATION FOR NEW MEMBERS

Diabetes is the general term to describe people who have blood that is sweeter than normal. A number of different types of diabetes exist.

A diagnosis of diabetes tends to be a big shock for most of us. It’s far from the end of the world though and on this forum you'll find well over 235,000 people who are demonstrating this.

On the forum we have found that with the number of new people being diagnosed with diabetes each day, sometimes the NHS is not being able to give all the advice it would perhaps like to deliver - particularly with regards to people with type 2 diabetes.

The role of carbohydrate

Carbohydrates are a factor in diabetes because they ultimately break down into sugar (glucose) within our blood. We then need enough insulin to either convert the blood sugar into energy for our body, or to store the blood sugar as body fat.

If the amount of carbohydrate we take in is more than our body’s own (or injected) insulin can cope with, then our blood sugar will rise.

The bad news

Research indicates that raised blood sugar levels over a period of years can lead to organ damage, commonly referred to as diabetic complications.

The good news

People on the forum here have shown that there is plenty of opportunity to keep blood sugar levels from going too high. It’s a daily task but it’s within our reach and it’s well worth the effort.

Controlling your carbs

The info below is primarily aimed at people with type 2 diabetes, however, it may also be of benefit for other types of diabetes as well.

There are two approaches to controlling your carbs:

• Reduce your carbohydrate intake
• Choose ‘better’ carbohydrates

Reduce your carbohydrates

A large number of people on this forum have chosen to reduce the amount of carbohydrates they eat as they have found this to be an effective way of improving (lowering) their blood sugar levels.

The carbohydrates which tend to have the most pronounced effect on blood sugar levels tend to be starchy carbohydrates such as rice, pasta, bread, potatoes and similar root vegetables, flour based products (pastry, cakes, biscuits, battered food etc) and certain fruits.

Choosing better carbohydrates

The low glycaemic index diet is often favoured by healthcare professionals but some people with diabetes find that low GI does not help their blood sugar enough and may wish to cut out these foods altogether.

Read more on carbohydrates and diabetes.

Over 145,000 people have taken part in the Low Carb Program - a 10 week structured education course that is helping people lose weight and reduce medication dependency by explaining the science behind carbs, insulin and GI.

Eating what works for you

Different people respond differently to different types of food. What works for one person may not work so well for another. The best way to see which foods are working for you is to test your blood sugar with a glucose meter.

To be able to see what effect a particular type of food or meal has on your blood sugar is to do a test before the meal and then test after the meal. A test 2 hours after the meal gives a good idea of how your body has reacted to the meal.

The blood sugar ranges recommended by NICE are as follows:

Blood glucose ranges for type 2 diabetes

• Before meals: 4 to 7 mmol/l
• 2 hours after meals: under 8.5 mmol/l

Blood glucose ranges for type 1 diabetes (adults)

• Before meals: 4 to 7 mmol/l
• 2 hours after meals: under 9 mmol/l

Blood glucose ranges for type 1 diabetes (children)

• Before meals: 4 to 8 mmol/l
• 2 hours after meals: under 10 mmol/l

However, those that are able to, may wish to keep blood sugar levels below the NICE after meal targets.

Access to blood glucose test strips

The NICE guidelines suggest that people newly diagnosed with type 2 diabetes should be offered:

• structured education to every person and/or their carer at and around the time of diagnosis, with annual reinforcement and review
• self-monitoring of plasma glucose to a person newly diagnosed with type 2 diabetes only as an integral part of his or her self-management education

Therefore both structured education and self-monitoring of blood glucose should be offered to people with type 2 diabetes. Read more on getting access to blood glucose testing supplies.

You may also be interested to read questions to ask at a diabetic clinic.

Note: This post has been edited from Sue/Ken's post to include up to date information.
Take part in Diabetes.co.uk digital education programs and improve your understanding. Most of these are free.

• Low Carb Program - it's made front-page news of the New Scientist and The Times. Developed with 20,000 people with type 2 diabetes; 96% of people who take part recommend it... find out why
  
  
• Hypo Program - improve your understanding of hypos. There's a version for people with diabetes, parents/guardians of children with type 1, children with type 1 diabetes, teachers and HCPs.
  

 

[Deleted Account]

Looking at the graphs on Glimp with my finger prick readings super imposed, the last few Libre have been more accurate.
But ...
Only when you take into consideration the 15 minute (sometimes more) delay.
The Libre is totally useless for me to get accurate results whilst I am exercising as my BG changes very quickly (10.3 to 3.1 in 30 minutes, yesterday). Therefore, I could not trust it (or any CGM) for hypo alerts; I have to rely on my hypo awareness in situations like that.
So, maybe, for me it is not the inaccuracies per se but the delay which is why I would not trust it for dosing or hypo alerting.

 

[jrussell88]

If you have an NFC-enabled Android mobile, try Glimp. It calibrates the Libre sensor with your fingerstick readings.

Bear in mind that fingersticks also aren't 100% accurate; clean your finger before testing and it may be worth doing a second fingerstick if there's an unexpected result.

Other than that, there is a slight lag, around 15 minutes, which matters if your BG is changing rapidly.

 

[tim2000s]

Abbott are now working up their generation 2 version of libre, which is going to send (very primitive) hypo/hyper alerts to the reader.

Being picky, the sensor will be sending the same data that MiaoMiao currently sends. The reader will just be interpreting it as High/Low/Okay rather than giving a glucose value.

 

[Deleted Account]

If you have an NFC-enabled Android mobile, try Glimp. It calibrates the Libre sensor with your fingerstick readings.

Bear in mind that fingersticks also aren't 100% accurate; clean your finger before testing and it may be worth doing a second fingerstick if there's an unexpected result.

Other than that, there is a slight lag, around 15 minutes, which matters if your BG is changing rapidly.

I am a Glimp user and find it very useful both with the calibration and it shows the finger prick readings on the Libre graphs - seeing finger pricks and Libre readings together confirmed the 15 minute delay, giving me more confidence in Libre.