Comparison Accu-Chek Instant vs Accu-Chek Active

The type determines the general operating principle of the blood glucose monitor. There are photometric, electrochemical, biosensory ones.

— Photometric. Blood glucode monitors employing color changes in test strips analyze blood composition. These devices assess the color of a test strip with applied blood, compare it to a stored standard, and deduce information about blood composition, particularly glucose levels. This technology, considered outdated, is now rare due to its limited accuracy and the fragility of its optical systems, requiring careful handling.

— Electrochemical. Devices of this type use test strips with reagents that, when reacting with glucose, produce an electric power; The strength of this power determines the blood sugar level. Such devices are quite simple and reliable, at the same time very accurate. The vast majority of modern glucometers operate on the electrochemical principle.

— Biosensory. The term "biosensory" encompasses various operational principles, depending on the blood glucose monitor model. Some devices improve the electrochemical method by incorporating amperometry and coulometry (measuring electric charge). Others use specific technologies like surface plasma resonance. Certain blood glucose monitors of this kind feature a sensor constantly on the skin, drawing blood through a needle immersed in the...body, allowing measurement by holding the device to the sensor. Ongoing developments include biosensor technologies that eliminate the need for blood sampling, enabling blood sugar determination through analyzing saliva, sweat, and other biological fluids. There's potential for such technologies to be introduced in the near future.

The measurement time of a blood glucose monitor is the duration from inserting a test strip with a blood sample into the device to receiving the result. While a shorter measurement duration theoretically enhances convenience by reducing the time spent on measurements, most modern blood glucose monitors complete this process in under 20 seconds, causing minimal inconvenience. Therefore, seeking the fastest model may not be particularly meaningful in practical terms.

The maximum number of test results that a blood glucose monitor can store at once is crucial for monitoring changes in blood composition. The built-in memory of blood glucose monitors is highly convenient, automatically saving data without requiring extra steps from the user. Additionally, many devices can enhance measurement results with supplementary information, including date, time, and food markers.

Knowing the frequency of measurements and the amount of memory, you can determine how long this memory will last before overflowing. For example, if the device is designed for 500 results, and measurements are taken 4 times a day, then measurements can be stored in the built-in memory for 500/4 — 125 days, that is, about 4 months.

— Test. To verify the functionality and accuracy of a blood glucose monitor, a control solution test is typically performed. This involves applying two control solutions with known glucose concentrations to the strips instead of blood. If the blood glucose monitor readings align with the expected values of the solutions, it indicates proper functionality. Periodic performance tests, ideally conducted weekly, are recommended, especially in cases of doubt about measurement results, such as discrepancies with one's health status.

— No food intake. The mode of measuring blood counts on an empty stomach, before meals. It is used, in particular, to diagnose diabetes in the early stages, as well as to evaluate the effectiveness of drug-free (with the help of a diet) treatment of type 1 diabetes. Analysis data is stored in memory marked "on an empty stomach"; this allows you to track the trend over time.

— After eating. The mode of measuring blood parameters "on a full stomach", after eating. It is used, in particular, in insulin-dependent diabetes — to evaluate the effectiveness and correct the current dosage of insulin. The measurement results are stored in memory marked "after eating" in order to make it easier to track changes over a certain period of time.

Options for averaging results provided in the blood glucose monitors.

Averaging is the derivation of the average measurement result (primarily the average glucose level) over a certain period. The need for such calculations is due to the fact that with individual measurements, the indicators are affected by momentary factors, while the general trend must be determined by average numbers. In modern blood glucose monitors, averaging can be provided for different periods — from 1 day to a quarter.

Measuring range provided by the blood glucose monitor. It is indicated by the level of glucose in the blood that the device is able to detect — from the minimum to the maximum.

Most blood glucose monitors have a measurement range with a safety margin to cover relevant human values. The lower limit is typically no higher than 1.6 mmol/L, corresponding to severe hypoglycemia requiring immediate medical attention. Similarly, the upper limit in most models is around 27 mmol/L or higher, exceeding critically high values. In practical terms, a patient is more likely to fall into a coma than to surpass the blood glucose monitor's measuring range.

The minimum amount of blood required for testing. The average volume of a drop of blood released when pricked with a lancet is 1 µl; that is, if the sample volume is larger, a little more blood will need to be squeezed out.

Note that in fact, the volume can be taken with a margin — most blood glucose monitors work normally even with more blood than necessary. But too little material leads to serious inaccuracies in the readings, so this parameter should not be neglected.

The hematocrit values for which the device is designed.

Hematocrit reflects the overall red blood cell count in the blood, influencing blood viscosity and electrochemical properties. Glucometers are calibrated for specific hematocrit ranges. When these limits are surpassed, inaccuracies arise — low hematocrit levels can lead to device overestimation, while high levels can result in underestimation.

Modern blood glucose monitors typically have a hematocrit range of 30 – 50%, which effectively encompasses normal adult blood viscosity values (36 – 48%). Issues may only arise in cases of significant deviations from the norm. Some devices offer an even broader operating range.

The encoding method provided in the device.

Encoding involves configuring the device for a specific set of test strips. This is necessary because test strips of the same type in different packages may contain different reagents. To ensure precise results, the device must be adjusted to a particular batch of strips, although there are exceptions — details below.

— Codeless. Codeless blood glucose monitors are the most convenient and cost-effective option. However, they are less accurate because they don't account for the specific features of the test strips in their design, potentially introducing some error in measurement results. Despite this, the margin of error is often negligible, making them suitable for certain user categories, especially the elderly who may appreciate the simplicity of use without unnecessary settings.

— Chip. Encoding using a replaceable chip. Such a chip is supplied with each package of test strips and is installed in the metre before using the package. Changing the chip is much easier and more convenient than entering the code manually (see "Code"), this option is quite popular in modern blood glucose monitors.

— Automatic. Automatic encoding, requiring no additional user actions, involves applying a code to each test strip. The device reads this code during use, automatically adjus...ting to the specific characteristics of the strip. This option is both convenient and accurate, but the consumables for such devices can be relatively costly. — Code. Manual encoding requires users to enter the code from a new pack of test strips into the monitor before use. While cost-effective and fairly accurate, this method can be inconvenient for some users, especially the elderly. Given the availability of more advanced and user-friendly encoding technologies, devices with manual code entry are uncommon.