Interstitial fluid

[Tron2112]

I've read on the forum that this stuff can skew your reading. I wondered if it skews the reading upwards or down? If its not blood, would it not dilute the blood and result in a lower reading? Unless it contains glucose too, in which case would it have the same concentration as blood?

Any armchair biochemists able to help with my query?


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[phoenix]

I don't think it's as simple as below or above, it depends on what is happening to the glucose levels at the time, are they moving as after a meal/exercise or are they in a steady state?
This study reviews the evidence
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2903977/
Reading it, I don't think that we can quantify it and certainly not use the info in any meaningful way.
it is more likely to be similar during times of steady glucose levels but when moving there is a time lag . Concentrations in interstitial fluid have been reported as between 0-45min behind that in plasma . On the other hand levels in IF may be much lower during and after hypoglycaemia.
Cgms which use interstial fluid for measuring glucose have to be calibrated several times with finger pricks and are most useful for showing the direction and speed of blood glucose change.

 

[Tron2112]

Wow! I wish I'd paid more attention in biology, some of that article is sinking in. It assumes understanding of a certain level.

I sometimes hold my finger tightly on the joint below the piercing to encourage blood flow. My pinkie always replies with an impressive doubling of the blood spot in time with my heartbeat. But is it IF or blood? Can I trust my reads via this method?





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