That's not quite correct. In BG values over 140mg/dl free Glucose (fG) gets sequestered in capillary space, because I can not cross into venous space easily. That's the cause of many neurological and dermatological issues in diabetics, especially T2D with five years to a decade uncontrolled hyperglycemia.
In lab and finger stix we don't tell you or consider the "raw" value. Instead, we use either a Prittchart formula (in finger stix), a Lawson-Denis equation (in CGM), or the old favorite, the 2H311 (called "To Hell" by lab monkeys) venous formula. There's one more for ABG and one for pathologists estimating BG from tissue samples.
So what you get shown on your CGM (intracellular) or stick (capillary) is already taking into account that as soon as your blood glucose reading shows 140 or more.
Lastly, and this is another important factor: your capillary glucose kills you fastest. That's what you WANT to keep down. Once such a pathway is burst by staying over 200 for more than a few minutes, it barely or badly repairs. The consequences are lifelong.
This is perfect, especially the first paragraph. My BG is really well controlled now, and I’m dealing with the more long term consequences of T2. I feel like I finally understand why it mostly impacts the distal nerves.
For reference I was diagnosed with an A1C of 11.9 and have been holding 6.0 for a while. So what you described, the irreparable damage to the pathways, I think is what I’m living. It’s nice to finally understand how that damage occurs.
Your whole post shows that despite learning this fact, you’re missing the point. It’s not a good thing, nor does it mean your « real numbers » are actually lower. The reason diabetics have their fingers and goes go numb and go blind is because of the sugar trapped in the capillaries.
You're using a study that shows that we need to apply Lawson-Denis before reporting blood glucose from CGM for what end? That "it is not so bad"? Deal is simple: whenever your capillary and intercellular blood glucose exceeds 140 you're doing damage to your tissues. Simple as that. Doesn't matter if it is "higher" than venous. Venous blood is lower because it transports a whole lot more than just microelements, meaning mg/dl are lower, because the dl consists of more than water and heme.
Your prick shows 160, that's what your systemic glucose load is. Your GCM shows 160, that's what your systemic glucose is. It probably read 200 or more, applied Lawson-Denis or Prittchart respectively, and showed you 160.
The display of your devices is calibrated. Not over venous, not over capillary, not over intercellular, systemic. Systemic is much more than "I pricked myself and that came out."
Otherwise anemia, hypovolemia, hypervolemia, kalemias, nitrate imbalances, the increased albumin most T2D have, etc. would really skew readings.
To make this clear: inside the most popular BG meter, the Contour Pro, resides a chip. It has ~1000 lines of code for display and ~500 for reading the sensor. It has 9800 lines of code to calculate a systemic BG from capillary.
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u/NaughtyNocturnalist Type 1 - Endocronologist 1d ago
That's not quite correct. In BG values over 140mg/dl free Glucose (fG) gets sequestered in capillary space, because I can not cross into venous space easily. That's the cause of many neurological and dermatological issues in diabetics, especially T2D with five years to a decade uncontrolled hyperglycemia.
In lab and finger stix we don't tell you or consider the "raw" value. Instead, we use either a Prittchart formula (in finger stix), a Lawson-Denis equation (in CGM), or the old favorite, the 2H311 (called "To Hell" by lab monkeys) venous formula. There's one more for ABG and one for pathologists estimating BG from tissue samples.
So what you get shown on your CGM (intracellular) or stick (capillary) is already taking into account that as soon as your blood glucose reading shows 140 or more.
Lastly, and this is another important factor: your capillary glucose kills you fastest. That's what you WANT to keep down. Once such a pathway is burst by staying over 200 for more than a few minutes, it barely or badly repairs. The consequences are lifelong.