Freestyle libre availability

[novorapidboi26]

The Libre sensor is an NFC device - it can store internally up to eight hours of readings - so must be polled at least every 8 hours
to show continuous readings.

So, lets say I wanted to carry out a basal test overnight with the Libre....

Will I get a different picture with the Libre than I would simply testing blood before bed and on waking?

 

[bamba]

You would get a different picture because:
a The Libre is not directly measuring blood glucose but glucose levele in interstitial fluid.
b levels in interstitial fluid lag behind blood levels.
c there is adiffence between immediate readings shown on the libre and the values stored in the sensor cache.
d some people have reported "flatline" reading if they go to sleep on the sensor.

However
Taking a direct reading only on going to bed and then on rising gives you only two readings aon no idea what happened between.
A Libre will be taking readings all night for you eo see in the morning - to how how supper was dealt with - or whether you are having mini hypo's.

 

[Engineer88]

So, lets say I wanted to carry out a basal test overnight with the Libre....

Will I get a different picture with the Libre than I would simply testing blood before bed and on waking?

Depends on how accurate you find libre also. I would trust dexcom implicitly (rarely more than 1mmol difference) but would need to see how accurate libre is for me personally.

But yes as long as before bed scan and waking scan are 8 hours or less apart you would get a continuous graph rater than two points which are never a straight line between them

 

[novorapidboi26]

Depends on how accurate you find libre also. I would trust dexcom implicitly (rarely more than 1mmol difference) but would need to see how accurate libre is for me personally.

But yes as long as before bed scan and waking scan are 8 hours or less apart you would get a continuous graph rater than two points which are never a straight line between them

But it the line between those points just made up?

 

[Engineer88]

But it the line between those points just made up?

No not on the libre, itll be actual results just stored on the sensor side which cant get to the reader without scanning

 

[Rokaab]

But it the line between those points just made up?

No, the sensor does a reading either every minute or every 5 mins (I can't remember which), and that data is stored on the sensor, but it only has enough space for 8 hours worth of data so will start getting overwritten after that - and when it's scanned with the read or phone the reader/phone gets all that data from it.

Edit: oops, every 15 mins

 

[bamba]

The line will be made up of readings taken/stored every 15 minutes.

I believe you can get a bluetooth device (??nightrider??) that can read and transmit the readings every minute to a computer.

https://www.freestylelibre.co.uk/libre/help/faqs.html
How frequently does the sensor capture and store glucose readings?
The sensor automatically measures glucose levels every minute and stores readings at 15-minute intervals for 8 hours. When the sensor is scanned by the reader, the sensor automatically transmits 8 hours of data to the reader.

If the sensor is storing glucose readings every 15 minutes, does that mean I will get the same glucose reading if the sensor is scanned again within the same 15 minute interval?
No, you will get the most current reading every time you scan the reader over the sensor.

What will happen if I scan frequently, for example, every 30 seconds?
You can scan as often as you want, but the reading will never change more frequently than every 60 seconds.

Why does the reader log data every 15 minutes? Why not more often?
To keep the sensor profile small it has a limited storage capacity. To make sure it could hold 8 hours of data (for a typical overnight period).

 

[novorapidboi26]

No, the sensor does a reading either every minute or every 5 mins (I can't remember which), and that data is stored on the sensor, but it only has enough space for 8 hours worth of data so will start getting overwritten after that - and when it's scanned with the read or phone the reader/phone gets all that data from it.

Edit: oops, every 15 mins

Thanks, so that's good then......

the sensor takes a reading every 15 and stores up to 8 hours.....

to access that data, you do a scan.....right?

 

[Rokaab]

to access that data, you do a scan.....right?

Yep
The reader/phone then holds the all data so you have a lovely graph.

If you use both a reader and a phone they don't talk to each other so you have to scan with both to get all the data on both - I use both, the reader I find is much easier to use quickly and discretely (like in the middle of a work meeting) but the phone app has a much better interface for looking at stuff.

 

[Stronggirlsclub]

I’m a little confused. Not by the technology but the availability.

If I wanted to scan with my phone would I just need to buy the sensor? And if so, where can I get them from?

Thank you

 

[urbanracer]

I’m a little confused. Not by the technology but the availability.

If I wanted to scan with my phone would I just need to buy the sensor? And if so, where can I get them from?

Thank you

£35 in Superdrug, around £45 in Boots, Lloyds, Asda and Tesco pharmacies. You will need to order them as they are not usuallly kept in stock.

 

[Stronggirlsclub]

£35 in Superdrug, around £45 in Boots, Lloyds, Asda and Tesco pharmacies. You will need to order them as they are not usuallly kept in stock.

Great thank you.

If I use the app, is it just the sensor I will need to buy?

 

[urbanracer]

Great thank you.

If I use the app, is it just the sensor I will need to buy?

I think you can get away without the reader if you're only intending to use your phone.

 

[DavidGrahamJones]

But it the line between those points just made up?

From https://www.nice.org.uk/advice/mib1...e-for-glucose-monitoring-pdf-2285963268047557:

The sensor is a few centimeters in diameter and is designed to stay in place for 14 days. It is applied to the skin, usually on the upper arm. A thin (0.4 mm), flexible and sterile fibre within the sensor is inserted in the skin to a depth of 5 mm; most people
have described this as being painless. The fibre draws interstitial fluid from the muscle into the sensor , where glucose
levels are automatically measured every minute and stored at 15-minute intervals for 8 hours. Glucose levels can be seen at
any time by scanning the reader over the sensor.

So if you choose to scan you will get an reading of that minute, but if you don't scan for 8 hours it will have a reading every 15 minutes stored on the reader. So nothing is made up.
.

 

[novorapidboi26]

From https://www.nice.org.uk/advice/mib1...e-for-glucose-monitoring-pdf-2285963268047557:

The sensor is a few centimeters in diameter and is designed to stay in place for 14 days. It is applied to the skin, usually on the upper arm. A thin (0.4 mm), flexible and sterile fibre within the sensor is inserted in the skin to a depth of 5 mm; most people
have described this as being painless. The fibre draws interstitial fluid from the muscle into the sensor , where glucose
levels are automatically measured every minute and stored at 15-minute intervals for 8 hours. Glucose levels can be seen at
any time by scanning the reader over the sensor.

So if you choose to scan you will get an reading of that minute, but if you don't scan for 8 hours it will have a reading every 15 minutes stored on the reader. So nothing is made up.
.

Cheers, its clear now.....