Phone scanning Libre vs Reader scanning Libre

[Lily123]

I know there’s only a difference of 0.2 but these were taken within the same minute so how are they reading differently?

 

[Loobyloo]

I would be happy with that mine is at worst 5.2 on libre and 8.6 on meter. Customer services said 1-2mmols differerence is acceptable (They are sending me replacement sensor). So what you have is very close.

 

[Lily123]

I would be happy with that mine is at worst 5.2 on libre and 8.6 on meter. Customer services said 1-2mmols differerence is acceptable. So what you have is very close.

What I put must have been confusing. I meant that the reader for the libre (scanning the sensor) read 0.2 lower than my phone scanning the libre sensor within the same minute

 

[Loobyloo]

Ah sorry misunderstood. My BG tester can read different on every jab so i suppose these are the same. None claim to be 100% accurate.

 

[Proud to be erratic]

I know there’s only a difference of 0.2 but these were taken within the same minute so how are they reading differently?
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If I got that I'd be content. The difference of 0.2 is wholly within the accuracy of the 2 devices, your reader and your iPhone. In real terms you can round the number down to 6 for both. When you consider the estimating that is routinely in an accurate carb count, there is no point in getting concerned over such a small difference.

Incidentally, I remember you saying in the "which pump" thread that you were going to weigh your cereal the previous evening, so you can get ahead of morning timings. One easy way to get a standard weighed amount of cereal is to use a volume measure. Decide what weight you want, then find a cup/ glass/ small bowl /small jug or any other container that holds exactly that weight - when full to exactly level. No heaping! Then every morning just use that container as your measure for your pre- weighed amount. Its quick and very "repeatable". Also works particularly well for liquids, eg milk. You can't overfill a container with a liquid.

 

[Lily123]

If I got that I'd be content. The difference of 0.2 is wholly within the accuracy of the 2 devices, your reader and your iPhone. In real terms you can round the number down to 6 for both. When you consider the estimating that is routinely in an accurate carb count, there is no point in getting concerned over such a small difference.

Incidentally, I remember you saying in the "which pump" thread that you were going to weigh your cereal the previous evening, so you can get ahead of morning timings. One easy way to get a standard weighed amount of cereal is to use a volume measure. Decide what weight you want, then find a cup/ glass/ small bowl /small jug or any other container that holds exactly that weight - when full to exactly level. No heaping! Then every morning just use that container as your measure for your pre- weighed amount. Its quick and very "repeatable". Also works particularly well for liquids, eg milk. You can't overfill a container with a liquid.

I thought the Libre took a reading a minute and then scanning twice within the same minute would get the same result? I must be confused with something else.

That is a good idea to try with the cereal but I’ve stopped eating cereal in exchange for yogurt and a Nature Valley bar (not enough time to get everything done in the morning, I wake up at ten to seven) If I do go back to cereal I will definitely use that for weight.

 

[rayray119]

I would be happy with that mine is at worst 5.2 on libre and 8.6 on meter. Customer services said 1-2mmols differerence is acceptable (They are sending me replacement sensor). So what you have is very close.

To be being 2 out is a bit to much for me I can deal with it being 1 out but I don't like the idea of something saying 5.4 for example when it couldbe 3.4

 

[Lily123]

To be being 2 out is a bit to much for me I can deal with it being 1 out but I don't like the idea of something saying 5.4 for example when it couldbe 3.4

Libre is calibrated to normal levels (I’m not sure what levels are regarded as normal in this sense) so the Libre might read higher at high numbers and lower at low numbers

 

[PattiEvans]

To be being 2 out is a bit to much for me I can deal with it being 1 out but I don't like the idea of something saying 5.4 for example when it couldbe 3.4

I think Lily is talking about 0.2 not 2mmol out.

 

[Lily123]

I think Lily is talking about 0.2 not 2mmol out.

I didn’t mean by a finger prick compared to Libre , I meant my phone and the reader both scanning the Libre within the same minute giving slightly different results. Yes I meant 0.2

 

[rayray119]

I think Lily is talking about 0.2 not 2mmol out.

Yes sorry I know proberry shouldn't have interumpted

 

[Lily123]

Yes sorry I know proberry shouldn't have interumpted

Nothing to be sorry for

 

[Lily123]

Hi @Lily123, I'm not sure if anyone else is following what you are saying, but I am. You are using the official Libre reader to scan your Libre sensor, and also scanning the same Libre sensor using the Libre app on your phone. They are showing a difference of 0.2
My best guess is that the algorithm used in the scanner device is older than the algorithm used in the app on your phone. Abbott are now concentrating on the phone app, and currently have no plans to release a scanner for Libre 3. So, further firmware updates for the Official scanner may or may not happen, but the software for your phone will be updated as required.

That was my thinking - that they were using slightly different algorithms but a difference of 0.2 isn’t that major it did confuse me

 

[Lily123]

The data received by both devices from the sensor is exactly the same, the algorithms interpret slightly differently, trying to reduce the lag that we notice when we compare against finger pricking. I assume the phone app should be doing a better job, most of the time.
The way to check if it is to reduce the lag, is to do the same comparison when your glucose level is dead flat. The values should be the same.

Yes I did scan again and both said 6.2 and stable

 

[Lily123]

Good.

I use the Libre app on my phone, side by side with the xDrip app. It's the same data going through both programs but different algorithms and in the case of xDrip calibrations to interpret that data. So, quite similar to your situation.

I have an iPhone so can’t use xDrip - I normally don’t use the reader but fancied a change and the alarms are less of an annoying sound on the reader

 

[Lily123]

I wasn't pushing xDrip, I just used it as an example

I know, it would be helpful for something like xDrip for iPhones or for xDrip to work on iPhones as calibrating the Libre would be helpful

 

[helli]

I know, it would be helpful for something like xDrip for iPhones or for xDrip to work on iPhones as calibrating the Libre would be helpful

There is a xDrip for iPhones. I think it is called xDrip4iOS.
i am afraid that, beyond the name, I know very little about it.

 

[Lily123]

There is a xDrip for iPhones. I think it is called xDrip4iOS.
i am afraid that, beyond the name, I know very little about it.

Ah, I may have to do some research about that

 

[Proud to be erratic]

I thought the Libre took a reading a minute and then scanning twice within the same minute would get the same result? I must be confused with something else.

No, I don't think you are confused. Although you are taking readings within 1 minute, perhaps within 20 seconds, you don't know whether the first reading was within the previous minute for the sensor and the second reading was from the next minute for the sensor!
When does sensor time start??? This philosophical (and unanswerable) question could become a great time waster!

 

[rayray119]

No, I don't think you are confused. Although you are taking readings within 1 minute, perhaps within 20 seconds, you don't know whether the first reading was within the previous minute for the sensor and the second reading was from the next minute for the sensor!
When does sensor time start??? This philosophical (and unanswerable) question could become a great time waster!

I thought it was every 5 minutes not every minute?