The key technology of blood glucose meter

Stability (CV value, coefficient of variation): Stability is an important indicator to evaluate the quality of the blood glucose meter. Because the relative error of the blood glucose meter is relatively large, such as blood glucose is 10, according to national standards, 8 or 12 can be considered accurate. However, if one machine measures these two results, it indicates that the stability of the machine is not good, and the stability is not good enough to make it difficult for the measurer to follow, and it is difficult to effectively guide the patient to take a treatment plan. Therefore, the stability of the blood glucose meter is very important. A stable blood glucose meter indicates that the test strips have good stability. Therefore, the more advanced the enzyme technology is, the better the manufacturer's product stability is.

Accuracy (SD value, standard deviation, correlation coefficient): As long as the stability of the test strip is good, you can adjust the password to make the measured value as close to the standard value as possible, that is, the so-called calibration. The premise of accuracy is stability, and there is no stability. Sexuality will not be accurate at all. The calibration standards and technologies of various manufacturers will be different. The accuracy of good products represents a good technique for factory calibration.

Set password technology: As it is a biochemical product, the process of culturing glucose oxidase (hereinafter referred to as enzyme) is very complicated, so the characteristics of each batch of enzymes will have some differences, so the current generated will be slightly different, so that each batch The test paper measurement results can be as close as possible to the standard values. The researchers will set passwords to adjust the differences between different batches of test papers so that the batch of test papers is as close as possible to the standard value. Therefore, setting the correct password is very important. Manufacturers' culture culturing and coding technologies are different, so it will affect the quality of each product.

Inter-assay difference: Because the production process of blood glucose test strips has strict environmental requirements, the manufacturer will make the measured values ​​as close as possible to the standard values ​​through calibration, but the difference between different batches of test strips is definitely better than that of the same batch of test strips. The difference between them is larger, which is the difference between batches; that is, the stability of the same batch of test strips is usually better than the stability between different batches, and the national standard's requirement for the difference between batches is not greater than 15 %.

Temperature compensation technology: As the enzyme is active, under normal circumstances, the activity of the enzyme does not change much more than 20 degrees. Below 20 degrees, the lower the temperature, the worse the activity. When the activity deteriorates, the current generated when reacting with glucose becomes smaller, so that the measurement result becomes lower. In order to measure the accurate blood glucose value at different temperatures, the researcher will pass the thermistor according to the real-time temperature condition. Adjust the resistance of the instrument so that the enzyme and the blood can produce currents that match the blood glucose level at different temperatures as far as possible, and then obtain the correct blood glucose level. This is the temperature compensation of the blood glucose meter. Since manufacturers have different formulas for blood glucose test strips, they will set temperature compensation parameters according to the characteristics of each test strip's enzyme. However, because the characteristics of the enzymes are difficult to grasp, the temperature compensation effects of various companies are uneven, and in general The closer the results are measured at different temperatures, the more advanced the product temperature compensation technology is.

Applicable temperature: Because the enzyme will be affected by temperature, so only under certain temperature conditions can measure blood glucose, the temperature compensation technology of each manufacturer in addition to determine the high and low temperature stability, but also determine the applicable temperature width of the blood glucose meter, each The use of blood glucose meters is slightly different, generally between 10-40 degrees.

The current status of core technologies in the industry The above six technologies are currently the key technologies in the blood glucose meter industry. The quality of the products of each manufacturer mainly depends on the above. For the time being, the above technologies and imported brands of domestic brands are relatively large. Gap, which is currently the major reason why most domestic brands of test papers are only about half the price of imported companies, but their sales are far inferior to those of international manufacturers. At present, almost all medical institutions use products that are imported brands. There is still a large gap between imports.

In fact, it is not difficult to make one or two batches of test papers with good stability and accuracy. The difficulty is that the stability and accuracy of each batch of test papers are very good. In fact, each plant includes international companies. It is difficult to absolutely guarantee that every time is very good. For example, Johnson & Johnson has recalled multiple batches of test strips due to error in the test strips in 2005. The technical differences among manufacturers are here. At present, the stability of most international companies can be controlled. Within 5%, the accuracy rate can be controlled to more than 95%, while small factories and domestic products are difficult to achieve the above level.

In short, the core technology of the rapid blood glucose monitoring system is more complex, and the technical differences between the plants can only tell who is better at this technology. At present, there is no such factory that has absolute certainty over all core technologies. Everyone is constantly During the exploration, the 2005 Johnsons and Beverages calibration event and the Roche FDA incident in 2007 all indicated that even if the top international companies do not have absolute confidence in the rapid blood sugar detection technology, these large manufacturers still do so, so the situation of those small factories can be imagined. Know.