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Is your gms often wrong?

Zhnyaka

Well-Known Member
Messages
816
Type of diabetes
Type 1
Treatment type
Insulin
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Homophobia, racism, sexism
I bought myself a gmc, and its readings sometimes differ from the readings of the glucose meter by 2 units. The glucose meter showed 6.9, and libre was 4.8, libre showed LO, and the glucose meter showed 3.2. Is this typical for libre or did I do something wrong during installation?
 
Mine usually read a bit lower than a fingerprick, especially the first day or two.
I do some tests at different times to get the 'feel' of a new sensor.
 
@Zhnyaka have you read the many threads describing the limitations of Libre?
You should not expect it to report exactly the same as finger pricks (two finger prick meters don’t report exactly the same) but it should be closer than 2mmol/l provided, it is not the first 48:hours after application, you are well hydrated nd the readings are not higher than 9mmol/l or lower than 4mmol/l.
 
this is still the first 48 hours. In general, 2 units is an acceptable fee for not having to pierce my fingers, but I am a little worried when the gmc showing LO despite the fact that I have very little hypoglycemia or no hypoglycemia at all
 
Zhnyaka said:
this is still the first 48 hours. In general, 2 units is an acceptable fee for not having to pierce my fingers, but I am a little worried when the gmc showing LO despite the fact that I have very little hypoglycemia or no hypoglycemia at all
Click to expand...
For future sensors, I recommend applying them 48 hours before activating.
 
In Response said:
For future sensors, I recommend applying them 48 hours before activating.
Click to expand...
Put the second gmc while the first one will work for another 48 hours, right? On the other hand?
 
How do we know which one is correct? We are comparing apples with pears surely?
Venus capillary draw compared to interstitial fluid (sensor)?
 
NicoleC1971 said:
How do we know which one is correct? We are comparing apples with pears surely?
Venus capillary draw compared to interstitial fluid (sensor)?
Click to expand...
If my Libres have read lower than blood by 0.8 to 2 mmol/l for 5 years now, measured at times of little change in BG.
If the Libre predicted hba1c has been off by exactly how much you'd expect based on the difference in readings for the same 5 years. (8 mmol/mol every time so far.)
If blood glucose meters have stricter requirements on accuracy than CGM's and Libres.

I can confidently state my Libres read lower than blood, and blood is the more reliable one.
 
NicoleC1971 said:
How do we know which one is correct? We are comparing apples with pears surely?
Venus capillary draw compared to interstitial fluid (sensor)?
Click to expand...
Shouldn't apples and pears have the same taste in our case? Now I think that the device, the readings of which correspond to my well-being, is correct.

I have never wondered if the glucose level in my interstitial fluid corresponds to the glucose level in the venus capillary
 
I think it is a time lag thing and perhaps blood draw is more reliable in terms of synching with your brain's hypo sensors.
I am not interested enough and far too lazy to check but do get decent warnings of hypo and hyper and then there's the vertical drop and alarm to tell me to take action.
 
NicoleC1971 said:
I think it is a time lag thing
Click to expand...
It's not, or the difference in hba1c wouldn't be perfectly in line with the difference between sensor and a fingerprick. It also can't be a time lag thing when the difference is there when I'm stable for hours.
NicoleC1971 said:
perhaps blood draw is more reliable in terms of synching with your brain's hypo sensors.
Click to expand...
With hypo's, yes, I see them first with a fingerprick when the sensor hasn't noticed yet, but that was not what I was talking about. I'm talking about sensors consistently reading lower than a fingerprick, no matter what the actual number is. For some of us it is a thing. I can work with it, both by doung double checks and with mentally adjusting the numbers (and using an alternative app which thankfully can be calibrated.).

I'm very lucky to have an endo who believes me, or she'd have me treating 'hypo's' between 4 and 6 with a fingerprick all the time.
 
Zhnyaka said:
Which app are you using?
Click to expand...
DiaBox.
It currently doesn't work on iPhones but it does on phones using android.
Are you on Facebook?
If so, you want to join this group: https://www.facebook.com/groups/974278412920319

The app cannot be found in the app store, because it isn't an official app, and Abbott, the manufacturer of the sensors doesn't agree with us using those apps.
I'm happy to share a link to the app download, but it really would be better if you can join the group to read up on how to install it and to answer questions on it.
 
Unlicensed software is everything for my country. Facebook has been blocked by the government, but we still use it
 
Zhnyaka said:
Unlicensed software is everything for my country. Facebook has been blocked by the government, but we still use it
Click to expand...
In that case, join that group, but give a shout out if you need help!

Very glad to hear you and your fellow countrymen have found ways to circumvent the blocks!
 
Am doing a trial for Abbott at the moment. Wearing 3 sensors, only one of which I can read. Am having to do 4 blood tests a day with scans immediately after on the reader. They are scarily accurate. I normally do few blood tests apart from at the beginning and end of a sensors life. The discrepancy for me is similar to that between two BGMs. So for me the Libre is brilliant. The Libre 3s I am wearing at the moment are so tiny I do not know they are on. So so hope, it is not long before there is agreed access via the NHS. And that Apple get their compatible App sorted. Only available on Android at the moment and there is no reader.
 
As a T2 I used the original Libre sensors for a while.

I found
  • I needed to insert the new sensor 48 hours before the old one expired, otherwise it gave - mainly overnight - very inaccurate low readings for the first couple of days if I started it sooner. They needed time to settle in. I often wore both sensors on my same arm, but the Libre reader knew which was the activated one.
  • In general my sensors indicated 1-1.5 points lower than my finger prick tests. This was consistent, but I saw the same patterns from both types of results, just a difference in their actual levels.
See:
https://www.diabetes.co.uk/forum/threads/ive-got-the-libre-blues.178110/#post-2334864
 
Libre stopped working for me after I developed an allergy to the glue. I kept using it and Abbott sent me numerous replacement sensors and even readers (this was the libre 1) but in the end I had to come to the conclusion that my body didn't agree with the device, as the readings were literally all over the place ( a known issue if you have a reaction at the insertion site apparently).

I moved to dexcom and have managed to avoid the allergy (thank you cavillon cream) and it works fine, but I still get (very rare) occasions why it is completely out, usually at the beginning or end of a sensor. Dexcom also has the advantage that you can manually calibrate it, though the dexcom phone team don't like you to do this more than once per sensor and prefer you not to do it at all.

I still find that it can under read at the beginning of a sensor so insert it in the morning, as I don't enjoy unnecessary night time hypo alarms.

If I have a severe hypo I use a glucometer to check the size and timing of the drop. In general there is a bit of a lagbetween interstitial and blood glucose (the interstitial lags) so if you are anxiously waiting to see if your levels are stabilising or still dropping, a glucometer is more reliable.
 
Thank you very much! Diabox calibrated my sensor, and now its readings coincide with the readings of the glucose meter for half a day. I definitely like this app
 
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