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Diabetes patients need to conduct the “fingerstick” a few times a day. One of the mechanisms of "fingerstick" is to take small amount of blood sample and put it onto a test strip. The enzyme on the test strip reduces the glucose and the electronics of the glucose meter detect the redox species produced. However, this method is painful and increase the risk of infection.

Photonic sensing technology opens up a new method for non-invasive blood glucose concentration. According to an article of medGadget in 2013 (The link follows http://www.medgadget.com/2013/10/non-invasive-measurement-of-blood-glucose-levels-using-glucotrack-interview.html ), the non-invasive kind was invented. By simply clipping the earlobe (without puncturing the skin), the blood glucose concentration could be measured. Does anybody knows the working principle for that? Or, suggest a paper describing that?

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marked as duplicate by jonsca, Bez, ddiez, The Last Word, Mad Scientist Oct 23 '14 at 5:14

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  • $\begingroup$ Please don't cross-post your questions. $\endgroup$ – jonsca Oct 22 '14 at 23:31
  • $\begingroup$ I am sorry! I just don't know the two sites are connected somehow. $\endgroup$ – aloha Oct 23 '14 at 1:29
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I'm not exactly sure how it is done non-invasively in the manner you describe but suspect that it has to do with IR absorption spectroscopy. Glucose has distinct bands in the near-IR frequency range. So by illuminating the ear lobe and the capillaries in the surface, picking off the refracted light, and spectrally analyzing you should be able to determine the amount of glucose relative to some reference calibration.

I worked for a start-up company that did this semi-invasively for glucose measurements in the ICU. We drew a small blood sample and optically analyzed it in a glass cell using a scanning interferometer - then returned the blood to the patient.

The optical method that draws blood probably is the best approach with regards to accuracy - where you would like to get within 10 mg/dL - but it also has its problems including response to 'interferents' in the blood that can pose as glucose not to mention high cost for the interferometer and fouling of the blood access system.

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  • $\begingroup$ see inlightsolutions.com $\endgroup$ – docscience Oct 23 '14 at 3:29
  • $\begingroup$ Thanks for your sharing, docscience! What are the possible "interferents" in human blood if I am targeting glucose? $\endgroup$ – aloha Oct 23 '14 at 3:44
  • $\begingroup$ Other types of sugars, sugar alcohols, some more than others. I don't recall the list but remember mannitol was one of the interferents. Our experts were working on ways to eliminate interferents, I believe by utilizing multiple peak responses of glucose. $\endgroup$ – docscience Oct 23 '14 at 3:47

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