Choosing the right blood glucose meter

How do blood glucose meters work?
What are the most important features of a blood glucose meter?
What are the measurement principles of a blood glucose meter?

A blood glucose meter or glucometer is a device that measures the level of glucose in the blood. It is used by patients with diabetes to monitor their blood glucose levels and if necessary to help them regulate their insulin intake. They are generally used with test strips to collect droplets of blood. Nevertheless, alternatives that are less invasive and restrictive have emerged in recent years.

Given the prevalence of diabetes worldwide, the evolution of blood glucose monitoring systems is now a major global health concern.

There are also models designed specifically for the veterinary field.

How do blood glucose meters work?

Lifescan OneTouch Verio Flex

We can divide them into three different types: invasive, non-invasive and continuous.

Invasive: the measurement is made using a blood sample taken using a lancing device, lancets and test strips. These elements are often sold in kit form at the time of the first purchase. New strips and lancets then have to be replaced in pharmacies. Although constraining for the user, this type of blood glucose meter is the most accurate method of measurement.

Non-invasive (or minimally invasive): In recent years, the market has seen the arrival of various measurement systems in the form of physico-chemical sensors in contact with the measurement area, usually the arm.

Using the meter to scan the area gives you the blood glucose level almost instantly. This represents a real revolution for people with diabetes who no longer have to inject themselves half a dozen times a day or replace test strips and lancets. Nevertheless, there are limited options available on the market and the results so far have shown that the systems offered struggle to be as accurate as the invasive ones. Another disadvantage is the problem of sensors not staying in place.

Continuous Glucose Monitoring (CGM): in this case, the blood glucose meter offers the possibility of continuous measurement. The patient wears the device, usually on his or her arm, and takes it everywhere. This type of model generally has an implantable sensor with a remote transmission system. It measures blood glucose levels in the interstitial fluid. It also makes it possible to more accurately assess changes in blood glucose levels over a long period of time. The continuous system reduces stress for patients who no longer have to prick their fingertips every day. The continuous system has its own constraints, however, such as maintenance and learning to use

the device. Difficulties understanding and interpreting the data, sensor malfunctions and the difference in measurement between capillary blood glucose and the value displayed by continuous glucose measurement can be frustrating and may cause a user to decide not to use this type of device.

What are the most important features of a blood glucose meter?

A blood glucose meter must be adapted to each patient’s needs. Before buying a blood glucose meter, it is therefore necessary to take into account several factors such as ease of use and transport, the blood glucose measurement units displayed and the use of a chip (code).

Ease of use: the blood glucose meter interface must be intuitive and easily display the results and their description. Some models have a touch screen which is comfortable and easy to use. The device should preferably be of a size and shape that allows for a good grip.
Ease of transport: Since the patient must be able to measure their blood glucose level anywhere and at any time of the day, the ease of transport of the device is a very important factor to take into account. The patient will therefore be more inclined to choose a light space-saving model. Weight should not be a constraint, especially for young patients.
Blood glucose measurement units: Depending on the meter model, results may be given in g/l, mg/dl or in mmol/l. This can mislead a diabetic patient if he or she does not pay attention to the selected measurement unit (in the case of meters with multiple unit choices). The conversion of mg/dl to g/l is obtained by dividing the figure by 100. For example, if the meter is set in mg/dl and displays a result of 123, this means that the patient has a capillary blood glucose level of 1.23 g/l. The conversion from mmol/l to g/l is obtained by multiplying the mmol/l by 0.18.
Using a chip (or code): for some blood glucose meters, each box of test strips contains a specific chip that must be used and discarded after the box is finished. An incorrect adaptation of the meter/strip can lead to incorrect results. For meters that require this adaptation, it is essential to ensure before each measurement that the code displayed corresponds to the code on the test strip tube you are using. If this is not the case, no measurement should be made. There are also models that do not require a code to be entered to ensure the quality of the results.

What are the measurement principles of a blood glucose meter?

Several measurement technologies are currently on the market. They are mainly electrochemical (enzymatic) and fall into three categories:

By glucose oxidase
By glucose dehydrogenase
By glucose dye oxidoreductase

The results obtained may vary depending on the technology used. It is therefore always very important to use test strips that are compatible with the technology indicated on the meter.

Similarly, these different types of technology can interfere with some patients’ other treatment. Glucose-oxidase meters, for example, interfere with oxygen therapy. Meters using glucose-dye-oxidoreductase interfere with maltose and galactose, as well as polysaccharides or oligosaccharides contained in solutions for infusion. Maltose can be present in high concentrations in the blood, either directly (immunoglobulin preparations) or after metabolism (for example icodextrin used in peritoneal dialysis).

The risk of overestimating blood glucose results is therefore very high and should not be taken lightly. Often these counterindications are indicated on the blood glucose meters concerned, for example that it is prohibited to use the device in case of peritoneal dialysis.