Dulin/Shutterstock
Many people living with diabetes use continuous glucose monitors (CGMs) to track their blood sugar levels. These small devices, often attached to the back of your upper arm or abdomen, send data to an app on your phone. This allows you to see, in near real-time, how your blood sugar levels spike or drop depending on what you eat or how active you have been.
The benefits for people living with diabetes are obvious, as failing to keep abreast of blood sugar levels can be dangerous. But these devices are increasingly being advertised as health aids to the broader community, including health-conscious non-diabetics and elite athletes…..Continue reading….
Source: Non-diabetics are buying continuous glucose monitors – but are there actually any health benefits?
.
Critics:
A blood glucose meter is an electronic device for measuring the blood glucose level. A relatively small drop of blood is placed on a disposable test strip which interfaces with a digital meter. Within several seconds, the level of blood glucose will be shown on the digital display.
Needing only a small drop of blood for the meter means that the time and effort required for testing are reduced and the compliance of diabetic people to their testing regimens is improved significantly. Blood glucose meters provide results in various units such as eAG (mg/dL) and eAG (mmol/L), and may also estimate A1C levels.
These measurements can aid in classifying blood glucose levels as normal, prediabetic, or diabetic, facilitating effective diabetes management for users. While some models offer interpretative features that indicate the health status based on these results, not all meters provide this functionality, focusing instead on providing raw glucose measurements.
Users of blood glucose meters without interpretative features can utilize online calculators to determine their blood glucose status based on measured values. The cost of using blood glucose meters is believed to be a cost-benefit relative to the avoided medical costs of the complications of diabetes.
Recent advances include:
- alternative site testing, the use of blood drops from places other than the fingertips, usually the palm or forearm. This alternative site testing uses the same test strips and meter, is practically pain-free, and gives the fingertips a needed break if they become sore. The disadvantage of this technique is that there is usually less blood flow to alternative sites, which prevents the reading from being accurate when the blood sugar level is changing.
- no coding systems. Older systems required ‘coding’ of the strips to the meter. This carried a risk of ‘miscoding’, which can lead to inaccurate results. Two approaches have resulted in systems that no longer require coding. Some systems are ‘autocoded’, where technology is used to code each strip to the meter. And some are manufactured to a ‘single code’, thereby avoiding the risk of miscoding.
- multi-test systems. Some systems use a cartridge or a disc containing multiple test strips. This has the advantage that the user doesn’t have to load individual strips each time, which is convenient and can enable quicker testing.
- downloadable meters. Most newer systems come with software that allows the user to download meter results to a computer. This information can then be used, together with health care professional guidance, to enhance and improve diabetes management. The meters usually require a connection cable, unless they are designed to work wirelessly with an insulin pump, are designed to plug directly into the computer, or use a radio (Bluetooth, for example) or infrared connection.
Investigations on the use of test strips have shown that the required self-injury acts as a psychological barrier restraining the patients from sufficient glucose control. As a result, secondary diseases are caused by excessive glucose levels.
A significant improvement of diabetes therapy might be achieved with an implantable sensor that would continuously monitor blood sugar levels within the body and transmit the measured data outside. The burden of regular blood testing would be taken from the patient, who would instead follow the course of their glucose levels on an intelligent device like a laptop or a smartphone.
Glucose concentrations do not necessarily have to be measured in blood vessels, but may also be determined in the interstitial fluid, where the same levels prevail – with a time lag of a few minutes – due to its connection with the capillary system. However, the enzymatic glucose detection scheme used in single-use test strips is not directly suitable for implants.
One main problem is caused by the varying supply of oxygen, by which glucose is converted to glucono lactone and H2O2 by glucose oxidase. Since the implantation of a sensor into the body is accompanied by growth of encapsulation tissue, the diffusion of oxygen to the reaction zone is continuously diminished. This decreasing oxygen availability causes the sensor reading to drift, requiring frequent re-calibration using finger-sticks and test strips.
One approach to achieving long-term glucose sensing is to measure and compensate for the changing local oxygen concentration. Other approaches replace the troublesome glucose oxidase reaction with a reversible sensing reaction, known as an affinity assay. This scheme was originally put forward by Schultz & Sims in 1978.
A number of different affinity assays have been investigated, with fluorescent assays proving most common. MEMS technology has recently allowed for smaller and more convenient alternatives to fluorescent detection, via measurement of viscosity. Investigation of affinity-based sensors has shown that encapsulation by body tissue does not cause a drift of the sensor signal, but only a time lag of the signal compared to the direct measurement in blood.
A new implantable continuous glucose monitor based on affinity principles and fluorescence detection is the Eversense device manufactured by Senseonics Inc. This device has been approved by the FDA for 90 day implantation.Some new technologies to monitor blood glucose levels will not require access to blood to read the glucose level. Non-invasive technologies include microwave/RF sensing, near IR detection, ultrasound and dielectric spectroscopy.
These may free the person with diabetes from finger sticks to supply the drop of blood for blood glucose analysis. Most of the non-invasive methods under development are continuous glucose monitoring methods and offer the advantage of providing additional information to the subject between the conventional finger stick, blood glucose measurements, and overtime periods where no finger stick measurements are available (i.e. while the subject is sleeping).
Leave a Reply