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Whether you’ve been anticipating getting your hands on a Libre sensor or have had this thrust on you by your diabetes healthcare team, once you get it out the box (and I acknowledge that some people do stall at this stage), it's inevitable that you, and anyone else involved in your diabetes management, will have a myriad of questions regarding its use and other things related. Knowing where to go to get answers can be difficult itself but this article will hopefully prove a valuable starting point.
As well as answering some commonly asked questions, I’m going to address queries that are covered less often with the aim to help you quickly get onboard with making the most of this med tech. As you’ll see or hear often quoted – the Libre sensor is a gamechanger!
What have I learnt?
From my own experience, I suggest that the key to getting the most from the Libre system is to avoid making comparisons with other Libre users. Diabetes is a very individual condition and management for each of us T1s will vary, sometimes very widely, from day to day, if not by the hour or minute.
It’s natural for us to try to compare ourselves to others but it’s not a competition even if some days feel very much like we’re in a battle! There are so many factors that can affect our glucose levels so to compare our levels with others is virtually meaningless and can have a negative affect our wellbeing too.
My suggestion would be to look at your own data, in particular the patterns, and set your own individual (time in) targets and look for small wins that are realistic to You.
In joining the Libre club, don’t beat yourself up if you don’t achieve unicorns all the time, or at all, ever. Don’t expect a flat line of perfect control and don’t get disheartened by seeing what others are posting.
Why don’t sensor readings match with my finger prick tests?
This is the most frequently asked questions and is often a cause of many questioning the accuracy of the Libre. If you’ve had training on the Libre sensor you’ll understand that the sensor is measuring interstitial fluid as opposed to blood glucose when you finger prick.
Not surprisingly we’ve come to trust our meter readers and it’s not unexpected that many of us will look to see how the two compare. The first thing to note is that readers themselves are not accurate and that all devices including glucose meters have parameters which allow for variation. This is typically up to 20% meaning that finger prick readings can be inaccurate themselves by up to 20% - either way of the reading you obtain. As the Libre reader or Libreview (app used for scanning using a smartphone) also has a margin of error then there can sometimes be quite wide differences between the two types of measurements.
Another factor in considering accuracy is the timing of readings. There is a time lag of around 10 minutes in glucose readings from the senor compared to a finger prick test. So, for a better comparison of the two methods you would need to scan first and then carry out a finger prick test 10 minutes later.
The FreeStyle Libre is great tech for showing us data that was previously invisible and the trend arrows give us valuable insight so that we can adjust our management in a proactive way, but when we’re high or low, it’s back to the finger pricks for assessing where glucose levels are.
A further point to note it is really important to stay well hydrated as readings will be much more reliable when the body is hydrated.
And finally, remember that Abbott recommend that when you are at the extremes, low or high, then you should finger prick test to confirm your glucose level and take appropriate action. You should also do this if you have signs/feelings that do not correspond with a reading from your sensor.
Read also: 5 Actions that improve Libre sensor accuracy
What if I knock the sensor off?
The number one culprit for knocking a sensor off is a doorframe. You didn’t realise how often you rubbed up against doorways until now!
Fortunately, Abbott do replace sensors in some, limited circumstances. However, there are times when they won’t and then there’s the inconvenience of waiting for a replacement to arrive and having to resort back to finger prick testing if you don’t have a backup.
We designed Librebands to protect sensors in these circumstances and to transform the look of a medical device to a sports accessory. Why not take a look in our shop?
For reporting a sensor to FreeStyle Libre (Abbott) call 0800 170 1177 (in the UK) or use the online email form at https://www.freestylelibre.co.uk/libre/help/contact-us.html
How do I get the sensor to stay on for 14 days?
Your skin changes all the time and is a fact of life that young skin refreshes much more frequently than the skin of older people. As we age our skin is more likely to be drier with an accumulation of dead skin cells. And there are many other factors that have an impact on skin elasticity, some of which we control, like our diet and exercise, and others which we don’t such as our environment.
Good preparation will go a long way to improving the chances of a sensor sticking and key to getting good skin adhesion is to use the HELP approach - that is, hydrate; exfoliate; limit use of moisturisers and protect (with a Libreband).
The importance that hydration plays when wearing a sensor cannot be stressed enough and this means more than just drinking water. It's essential that the body retains moisture!
There's more about skin hydration in our blog WHY YOUR LIBRE SENSOR WON’T STICK (Part 1 of Libre Life, Summer Edition): https://lovemylibre.com/blogs/news/libre-life-sensor-skin-adhesion-hydration
There’s blood coming out of the sensor (on application). Is it ok?
It’s estimated that 1 in 100 will bleed when applying a sensor to the arm and the phrase you may often see online is that “bleeders are the best readers”. Whilst there’s nothing to confirm this to be true it is a widely used statement and it appears that so long as the blood flow stops then the readings will be fine.
If there are any concerns, you should always consult a healthcare professional.
How do I remove the sensor?
There are lots of explanations and YouTube videos online for explaining how to apply the Libre, but little mention of removal. This comes down to personal preference, but some of the popular suggestions of how to approach it are:
- Ease it off gently – it should lift.
- Pull with constant pressure.
- Rip it off like a plaster.
- Use baby oil or Tac Away Removal wipes (on Amazon) to loosen.
- Use an alcohol wipe to rub around edges.
And for future removals, it may be worth considering shaving the area where you’re placing the sensor in advance, as this can have an effect on adhesion and ease of removal too!
What is a CGM?
CGM is the anacronym for continuous glucose monitor. A CGM will send glucose level readings every 5 minutes to a reader or phone continuously i.e. ongoing through the day and night. The Libre is often referred to as a CGM but is in fact a flash glucose monitoring system as it relies on the user to scan the sensor to receive the readings stored in the sensor.
Many Libre wearers love the tech but want to get more out of it to improve their diabetes management and so will look to convert to a full CGM. This currently means purchasing a third-party transmitter, the most common of these being MiaoMiao, Bubble and BluCon NightRider. The main advantage of these products is that there’s no need to scan and readings are automatically updated every 5 minutes, there are alarms you can set for highs and lows and of increasing importance to users is the ability to see glucose levels on a watch or other device.
However, none of these products are approved for use with the FreeStyle Libre by Abbott, nor are they authorised by UK or European regulatory bodies. It’s worth noting that Libre 3 is due to be launched in the UK towards the end of 2021 and is expected to offer full CGM, so converting using a 3rd party may soon be unnecessary.
See our blog LIBRE SENSOR WITH BUBBLE, MIAOMIAO AND BLUCON: https://lovemylibre.com/blogs/news/libre-sensor-comparison-cgm-bubble-miaomiao-blucon
Should I join any online Forums for advice?
There are many forums, that relate to Libre sensors, in particular on Facebook, both UK based and globally. Some of the groups are heavily moderated and expect users to follow quite stringent rules such as not posting in the wrong group or what is determined as “off topic” although there is a group for this specifically (Abbott Libre Off Topic - https://www.facebook.com/groups/AbbottLibreOffTopic). Other users often expect new members to search the forum for answers, which isn’t always helpful if you don’t know exactly what you’re looking for. Having said that, they can be a valuable source of information and support too. Keep an eye on who owns the group too as some of these are run by individuals who have their own commercial interests to promote.
What is a Unicorn?
A unicorn is usually where your reader or iPhone chart shows that you were in range for 100% of the time. Look at the percentage shown under TIME IN TARGET on the home screen. Some users take this further and aim to show 100% in the target range i.e. green bar on a phone, on the TIME IN TARGET screen, which will relate to a longer period i.e. 7, 14, 30 or 90 days.
There’s also an alternative type of unicorn, when the glucose level shown by the Libre sensor which measures interstitial fluid is the same as a blood glucose meter reading.
For more terminology see our blog GETTING TO TERMS WITH THE LIBRE SENSOR : https://lovemylibre.com/blogs/news/libre-sensor-terminology-guide-diabetes
Will my HbA1c be the same as on the Libre app?
Another comparison that users try to make is between the predicted HbA1c shown on the Libre sensor and the result they’re given by a blood test carried out either by a GP surgery or hospital. Sometimes they will match, but more often than not, they don’t.
HbA1c is itself is an indirect measurement of average blood glucose over a period of 10-12 weeks, but it is not foolproof as it is based on an assumption that red blood cells have a lifespan of 90 days. However, this isn’t always true for those with diabetes and may skew the calculations. Another factor is that it is affected by whether the person has anaemia.
In addition, if you have lots of hypos then this may be reflected in the calculated HbA1c figure as the Libre is less accurate below 3.9 mmol/L and more readings in the lower range will affect the overall HbA1C figure shown.
This doesn’t mean that a HbA1c reading shown on the Libre is a not useful. In fact it’s a good guide to where your glucose levels are generally but as mentioned above there is a growing emphasis in diabetes care that time in target is more important than a HbA1C score.
Where can I get more information relating to using the Libre sensor?
Love My Libre is so much more than a shop, it’s intended to reflect the many aspects of daily life as a type 1 with a focus on wearing a Libre sensor. Whether it’s memes on social media, blogs on newsworthy topics, briefings on our YouTube channel or more extensive articles in our online magazine, Libre Life, we hope you’ll find our material engaging with resources relevant to your diabetes management.
We’re always keen to hear from customers and readers alike, so please do get in touch by email to email@example.com
Love My Libre is not associated or affiliated with Abbott or FreeStyle Libre. Content here and on our website www.lovemylibre.com does not constitute medical advice or replace the relationship between you and healthcare professionals nor the advice you receive from them.
The author of this blog has type 1 diabetes and uses the FreeStyle Libre 2 which is provided on NHS prescription.
FreeStyle Libre is a registered trademark of Abbott Diabetes Care Inc.