Poor rating for Freestyle Libre sensors

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DavidDK

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94
Type of diabetes
Type 1
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I have hopefully a quick question if I may please.

Does anyone know if the Freestyle Libre sensor contains any chemicals that react with the glucose taken by the sensor filament lodged in the interstitial fluid beneath the skin when in use?

I am curious whether the process is partly a chemical process similar to that used by some blood glucose test strips.

Thanks in advance
 
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Scott-C

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Hi, @DavidDK , yes, it's broadly similar to test strips.

The filament is coated with glucose oxidase, which is used in strips too, it reacts with passing glucose, oxidising it, a few other bits and pieces happen chemically, can't remember the details, but the upshot is that the chemical reaction gives off electrons proportional to the amount of glucose and those are measured electrically as a current, and then turned into an estimation of bg.

The glucose oxidase wears out after a while, which is why the sensors only last so long.

Here's a pic of another type of cgm showing what's going on:

may14_cgm_illo.jpg
 
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Bluetit1802

Bluetit1802

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I have worn 17 sensors. Not one has fallen off or been knocked off accidentally. At the end of the fortnight they have all been stuck like limpets to my arm. I don't wear any tape to hold them on. Admittedly I don't go swimming. I find them very difficult to remove. It is a struggle.
 
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DavidDK

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94
Type of diabetes
Type 1
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Scott-C said:
Hi, @DavidDK , yes, it's broadly similar to test strips.

The filament is coated with glucose oxidase, which is used in strips too, it reacts with passing glucose, oxidising it, a few other bits and pieces happen chemically, can't remember the details, but the upshot is that the chemical reaction gives off electrons proportional to the amount of glucose and those are measured electrically as a current, and then turned into an estimation of bg.

The glucose oxidase wears out after a while, which is why the sensors only last so long.

Here's a pic of another type of cgm showing what's going on:

View attachment 34502
Click to expand...

Thank you Scott-C. I am much obliged. I like to know how things work!
 
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Scott-C

Well-Known Member
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2,474
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Type 1
DavidDK said:
Thank you Scott-C. I am much obliged. I like to know how things work!
Click to expand...

Cheers, David, the ingenuity, engineering and technology behind them is pretty amazing (marred only by the fact that they are frequently very inaccurate!).

If you're interested in the subject, here's a link to a paper, A Tale of Two Compartments, which goes into the history, biology and technology of cgm - I found it to be a useful read when I was first getting my head round the quirks of cgm:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2903977/
 
therower

therower

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Messages
3,922
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Insulin
Scott-C said:
Hi, @DavidDK , yes, it's broadly similar to test strips.

The filament is coated with glucose oxidase, which is used in strips too, it reacts with passing glucose, oxidising it, a few other bits and pieces happen chemically, can't remember the details, but the upshot is that the chemical reaction gives off electrons proportional to the amount of glucose and those are measured electrically as a current, and then turned into an estimation of bg.

The glucose oxidase wears out after a while, which is why the sensors only last so long.

Here's a pic of another type of cgm showing what's going on:

View attachment 34502
Click to expand...
Scott this is brilliant. Also made me smile thinking how much it might scare the sh ....... living daylights out of someone who had no concept of size comparison.
 
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Scott-C

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Type of diabetes
Type 1
therower said:
Scott this is brilliant. Also made me smile thinking how much it might scare the sh ....... living daylights out of someone who had no concept of size comparison.
Click to expand...

Lol, yes, it looks pretty terrifying, although the 40 to 50yr dx'd squad will be saying, huh, we used to inject with barbed wire!
 
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Jaylee

Jaylee

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Retired Moderator
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Scott-C said:
Lol, yes, it looks pretty terrifying, although the 40 to 50yr dx'd squad will be saying, huh, we used to inject with barbed wire!
Click to expand...

Beaver built water obstruction straight, on that sentiment.... ;)
 
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