NIST researchers use cellphone compass to measure glucose
nist.gov
nist.gov
I fear that they, like so many organizations, must employ non-experts to interview experts and write stories. But getting the unit of concentration wrong? (Later in the sentence they do note that moles refer to quantity, not concentrations, so the whole sentence is self-contradictory.)
This problem is so common I think it might make sense to suggest a common solution. Perhaps an organization specializing in X ought to hire one member of the writing team who has a degree in X, to look over material before it goes out to the world. Or at least pay one of the experts on a per-case basis, say a day of salary for a half hour of work, to go over material before it is published.
They created a material that contracts/expands depending on measurement levels, and that can be detected by the magnetometer. But the sample needs to be deposited in it.
This is not a non-invasive glucose monitoring solution, and current under-skin devices will remain a lot more convenient.
A magnetometer costs $1-$5, plus a couple dollars for a microcontroller, what will likely happen is that this will result in a new breed of devices that offer laboratory precision at very low cost. The phone part is irrelevant.
They have a number of other potential applications, and it's rather clever and surprising. They could have led with any of those.
The problem is not that you can get a nicely correlated signal when holding a stationary phone against a stationary well of known concentration, the problem is how does your sensor perform when:
1. You're exercising (sweat getting between the sensor and the skin)
2. You're on vasoconstrictors (smoking or blood pressure medications)
3. You're taking medication that "looks" similar to glucose (in electrochemical sensors that's ~~ibuprofen~~ acetaminophen, but the number of magnetic analogues, especially in the presence of interference, is surely greater)
4. You have low perfusion
5. You're sleeping on/compressing the sensor. This changes how the blood flows, and needs to be accounted for or you'll risk reading a false low value.
These are just a handful of the problems that modern CGMs face, and only a few of them have working solutions.
The sample liquid containing glucose, e.g. wine or possibly blood (the sample might need to be diluted first with pure water) is put on a gel that has volume changes depending on the amount of glucose.
The volume changes are detected magnetically because the gel is coated with a ferromagnetic material.
If this were used for blood glucose, the blood would have to be extracted first by traditional means.
This does not seem to be the intended use, because the already existing invasive devices are more convenient.
The intended use appears to be for testing food using a device that contains the gel and to which you attach the smartphone in order to read the results.
The gel holder would substitute the sensitive strips that are used in such glucose measurement kits and the smartphone would replace the electronic reader that displays the results.
Nothing would change about the invasiveness of having to pierce the skin with needles, to extract blood.
There exist experimental devices for non-invasive measurement of the blood glucose, whose purpose is to avoid the use of piercing needles, but this new glucose sensor has nothing to do with those.
This new glucose sensor is for other uses and its advantage is that it no longer needs a special expensive electronic device for reading the sensor output, but a standard smartphone is good enough.
Huh, I never knew this. Does this mean taking ibuprofen can give you an elevated glucose reading on a blood test?
But yes, presence of acetaminophen with a naive electrochemical sensir will cause false high readings, which are VERY dangerous!
The latest generation of sensors have fixed this problem, but with any new sensing tech, you need to make sure you're learning from the mistakes of the past. With a new sensing paradigm, you won't necessarily have problems with the same drugs, but knowing that this kind of constructive interference is a potential problem will help you design a more robust system.
The bigger danger is being low, which will lead to unconsciousness, coma, and death.
Insulin brings down blood glucose. Getting insulin when not needed can be deadly. (It's a favorite of murder mystery writers.) False highs are more of a risk than false lows.
Which means you may need to administer sugar to a diabetic in an emergency. But unless you're a medical professional you will never need to give them insulin.
[1] Meet the inventor: Professor Adrian Porch from Cardiff University:
https://www.med-technews.com/medtech-insights/latest-medtech...
[1] Microwave Noninvasive Blood Glucose Monitoring Sensor: Penetration Depth and Sensitivity Analysis (2018)
https://ieeexplore.ieee.org/document/8428850
[2] Microwave noninvasive blood glucose monitoring sensor: Human clinical trial results (2017):
Not nearly accurate enough to make insulin dosing decisions, which is all diabetics care about.
For the foreseeable future, non-invasive glucose monitors will be like the scales that measure your body fat through electrical impulses. A neat toy, but not actually useful for medical purposes.
It might be all type-1 diabetics care about, but for the 90-95% of diabetics that are type-2 much less accuracy is needed.
I just don't know why you'd choose the less accurate thing when it's your health.
I think the non-invasive stuff makes the most sense for people who don't have diabetes yet. Nothing will be covered by insurance for them and the non-invasive tech might be cheaper, and it can nudge them to make healthier eating decisions.
How do people make this mistake
To determine if my body is burning ketones on a ketogenic diet, I used to have to pee on pH-sentitive keto test strips. Sounds like in the future I'll be peeing on my phone instead.
It’s cool, but nothing close to what’s described.
The linked Nature Comm paper seems pretty thorough, and they are reporting really high sensitivity (1000x what you’d need for typical blood glucose levels)