Most of us know that our Dexcom CGMs give us an “estimate” of our blood glucose as the sensor is inserted in interstitial fluid as opposed to blood. The CGM then uses an algorithm and gives us a proxy BG reading. [In addition, supposedly it is 10-20 minutes behind the actual BG reading especially if BG is rapidly rising or falling.]
Per the URL below, " Interstitial fluid acts as a kind of fueling station in terms of nutrients for our cells. Interstitial fluid contains glucose, salt, fatty acids and minerals such as calcium, magnesium and potassium. Interstitial fluid can also hold waste products which result from metabolism." The nutrients in interstitial fluid come from blood capillaries. (https://www.diabetes.co.uk/body/blood-vessels.html).
The sensor is in a fixed position in our body. I assume the interstitial fluid circulates in our body just as blood does. Any idea how long it takes interstitial fluid to circulate? Any idea how long it takes actual blood to circulate?
My question, after all this verbiage, “Are the components of Interstitial fluid uniform?” If not, is it possible that our CGM can give us a different readings simply because the fluid passing the sensor is not uniform?
Could that be a reason why the CGM can go way up or down 5 minutes later and then return? Could that be a reason why a CGM reading can be different from mater reading other than the 10-20 minute lag?
Anyone have any thoughts on this?