Non-Invasive Glucose Monitoring for Diabetes (2023)
Time to read 11 min
Time to read 11 min
The interest in non-invasive glucose monitoring devices is growing exponentially, and many companies promise to develop a solution to get accurate blood sugar readings without a drop of blood.
But are they close to hitting the shelves? Diabetics would certainly hope so. Getting glucose measurements without having to draw blood would make managing their condition much easier, whether they need continuous glucose monitoring or not.
However, though you might have many more options as a consumer, that doesn’t mean all these devices will effectively help you measure blood glucose. So, before making a decision, read this comprehensive guide to learn how non-invasive blood glucose monitoring works, its effectiveness, and more.
For diabetic patients, monitoring blood glucose levels is part of their daily routine. It helps keep blood sugar levels at optimal ranges and to determine whether a person’s treatment or lifestyle changes are effective.
Unfortunately, determining the blood glucose value at home using the standard devices may result in certain side effects, such as:
A standard glucose monitor also doesn’t account for diabetics with needle phobia, a condition that can make both blood glucose monitoring and diabetes treatment more difficult for those who are insulin-dependent.
The two most common types of permanent blood sugar monitoring devices are:
Around 70% of those who use CGM have type 1 diabetes and need continuous monitoring because they are insulin-dependent. However, people with type 2 diabetes or other forms of diabetes can still benefit from CGM devices, even if they don’t need insulin injections.
Unfortunately, device cost, health insurance status, and socioeconomic backgrounds create a firm barrier between most diabetics and these devices.
As a result, glucose meters are more widespread because they are relatively affordable, simple to use, and provide fairly accurate blood sugar readings.
There are several types of noninvasive blood glucose monitoring systems available that take widely different approaches.
But they all share the common criterion of being bloodless, meaning you don’t have to prick your finger to measure glucose levels.
Here’s a short breakdown of the three main types of non-invasive devices:
Optical methods provide glucose measurements by analyzing how a light beam is absorbed or scattered through tissue. There are several avenues such devices use to get their readings, but their core principle comes from the notion that glucose levels change the way light is reflected from human skin.
Think of this type of non-invasive glucose monitor as a smartwatch you wear on your wrist. The light coming from the back of the watch would have constant contact with your skin, allowing the device’s glucose sensors to provide a constant reading for your blood sugar levels, which you could get directly on the watch screen or even your smartphone.
These measure blood glucose levels by analyzing a sample taken in a non-invasive manner, such as sweat, tears, urine, or saliva.
The measurement process with these devices is different depending on the specific approach they take for detection. Here are a few possible examples:
The most common minimally invasive blood glucose monitoring device is the CGM. It involves getting a small glucose sensor inserted under the skin, either through a patch containing a microneedle or an implantable device.
The CGM measures the blood glucose from the interstitial fluid, which is found between the cells, in real-time. Patients can view their blood glucose levels, get warnings through a smartphone app if their levels are too low or high, and get charts to monitor their overall diabetes management.
However, the sensors in CGM devices need to be changed once every 7-14 days, depending on the specifications of the product. Implantable sensors may last longer.
Wearable devices today can offer you essential wellness information, from heart rate to blood pressure and even blood oxygen levels. So far, the results have been mixed regarding blood sugar for both devices designed for personal use and clinical settings.
Non-invasive blood glucose monitors are still far short in several ways:
Several companies have announced their interest in measuring glucose without blood samples, including some that don’t come from the healthcare sector. But the promise that you’ll soon have an Apple Watch able to measure glucose at all times is unrealistic.
John L. Smith, a well-known consultant and chemist, has been watching this industry for decades and documenting the attempts at non-invasive devices in a book called "The Pursuit of Noninvasive Glucose", which he updates every few years.
One important note made by the author is that companies tend to over-promise the abilities of their new devices before they gather the data to back up their claims.
These ideas were confirmed by a Diabetes Technology Society analysis published in 2021, which also warned that many of these claims are hyperbolic.
Smith also notes that the scientists working in these fields also tend to "lose their objectivity" when developing these devices and underlines that he doesn’t see much advancement in optical non-invasive monitoring in the last few decades.
The accuracy of many of these tools has come into question, which is why you don’t see many of them with FDA clearance.
But even with clearance and the clinical studies behind them, these devices still have a major problem showing accurate glucose concentrations in real time because of time delays.
There is a lag between the glucose levels in the blood and other samples used by non-invasive systems. For example, a CGM sensor that analyzes the interstitial fluid could show glucose levels with a 5 to 25-minute delay when compared to finger-pricking methods.
For a healthy person, these delays are not significant, but people with a diabetes diagnosis may still need to use glucose meters to get real-time glucose concentrations.
A major benefit of these devices is that they help people take a more proactive approach to their diabetes management.
For example, a CGM smartphone app could alert a person that their glucose concentration is too high or too low, in which case the patient could take immediate action before they began to feel the symptoms,
But this is a double-edged sword, especially when considering that these readings might not be accurate all the time. In these cases, the device wearer may be alerted that their blood glucose level is low (known as diabetic hypoglycemia) and be prompted to consume sugar and regulate their levels. Doing so when the reading is inaccurate spikes their glucose levels.
Non-invasive monitoring devices usually mitigate this risk by confirming the warning with a blood collection test before taking action.
Whether it’s minimally invasive or optimal methods, these products often promise to provide a simpler way to manage diabetes.
However, there can still be an associated learning curve depending on the type of device used, such as:
Before a new device to measure glucose can reach your household, it’s tested in various clinical trials to ensure both its accuracy and safety.
So far, the results have been underwhelming. One meta-analysis of fifteen studies with a total of 733 participants concluded that both minimal and non-invasive systems could not accurately measure hypoglycemia.
Another review noted that a person’s age, skin color, or skin condition can affect the measurement result of optimal methods and underlined the stronger need to calibrate these devices for each patient.
Overall, the clinical trials that have put these devices to the test don’t yet reveal a fully effective way to monitor glucose levels without having blood drawn.
Though the state of non-invasive glucose monitors is nowhere near where scientists and manufacturers hoped, there are still devices available that could provide a way to manage your condition without daily finger pricking.
Here are a few things to consider when choosing a device to monitor your blood glucose levels:
The physician who oversees your diabetes treatment is the best person to help you choose an appropriate way to monitor your blood sugar daily.
If you’re interested in CGM or similar devices, your physician can recommend a monitor based on both your specific needs and their extensive knowledge regarding how these devices have performed with other patients.
Migrating toward a new glucose monitor also involves an adjustment period, so your doctor may check in with you more often to see if the device is beneficial to you or even change your treatment plan if necessary.
Most health insurance plans cover glucose monitors such as meters and CGMs, but even so, you will likely still have some out-of-pocket costs to consider.
A CGM device may cost anywhere between $100 and $300 a month with no insurance, and you may still need to invest in a glucometer to double-check your glucose levels occasionally.
If you’re insured, you’ll need to check your policy to see how much the CGM or glucometer costs are covered. Note that if you want to invest in newer devices, like a wearable device that analyzes glucose molecules through visible light, these will likely not be covered.
The best glucose monitor is the one that makes it easy to manage your diabetes daily.
Choosing the right device may come down to what you’re comfortable using. CGMs may provide a way to continuously know your blood sugar levels, but some patients feel uneasy about having them physically attached to their bodies and also find the upkeep cumbersome.
Opting for a simple device you can learn to use correctly right away is the best method to ensure you'll follow your daily diabetes management plan without fail.
As a person with diabetes, you depend on the accuracy of the glucose sensor. It’s highly unlikely that medical professionals will recommend a device that did not perform well in clinical trials, but even so, you may want to do your research and assess the effectiveness of a diabetes monitor.
This approach can also reveal key information about the device that your physician did not mention or was unaware of, such as optimal ways to use it, possible side effects for implantable sensors, and more.
New glucose monitors can make managing diabetes easier by providing extra features such as real-time alerts when your levels change and even personalized recommendations regarding diet and lifestyle changes.
These features can support your efforts in managing diabetes, so they do matter when choosing the right monitor. However, you should never rely solely on the data or recommendations coming from these apps. Always refer to your physician for the right diabetes treatment approach.
The approaches to non-invasive glucose monitoring have several hurdles to overcome, and so far, researchers have not been able to successfully design a device that can meet the standards required for launch.
Non-invasive devices must reduce the time lag between the glucose levels in the blood and other sample fluids, account for each patient’s skin color and conditions, and successfully pass scrutiny in clinical trials before they can get FDA approval and be sold to people with diabetes.
Continuous glucose monitoring devices can be an effective way for people with type 1 and type 2 diabetes to manage their condition, especially if they need to check their levels several times a day.
While these devices are generally considered safe and reliable, many doctors still recommend using glucometers to confirm blood sugar levels in certain cases, such as if you’re changing your insulin dosage.
A world with effective non-invasive glucose monitoring may still be far away, but if you’re insulin-dependent, you can access a way to get your treatment without an injection.
Jet injectors use a nozzle to deliver liquid medication like insulin to the human body without a needle. Studies have noted that these needle-free devices achieve comparable accuracy in administering insulin and increase patient satisfaction tremendously.
Monitoring blood sugar through a true non-invasive monitor would provide you with a more convenient and less painful way to manage diabetes. Still, researchers and manufacturers have a long road ahead, leaving you to keep pricking their fingers for now.
But if you’re currently taking insulin, you can at least find solace in the fact that you don’t need any needles to administer your treatment through our effective needle-free solution.
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