A glucometer is a device for measuring the level of glucose in organic liquids ( blood , cerebrospinal fluid , etc.).
Glucometers are used to diagnose the state of carbohydrate metabolism in people with diabetes. Diabetes mellitus is a disease that occurs when the endocrine pancreas, which produces insulin (a peptide hormone that contributes to the supply of glucose to muscle and fat cells), is disturbed by the normal functioning of the pancreas . Using a glucometer, the blood glucose level is determined and, based on the data obtained, measures are taken to compensate for carbohydrate metabolism disorders.
There are several measurement techniques. Recently, portable glucometers for home measurements have become widespread. It is enough to apply a drop of blood to a disposable indicator plate installed in a glucose oxidase biosensor , and after a few seconds the concentration of glucose in the blood ( glycemia ) is known. For different laboratories, methods and apparatuses, glycemic norms are different, for the glucose oxidant method - 3.33-5.55 mmol / l , provided that the measurement was performed on an empty stomach. Within a few hours after eating, glucose levels are usually 1.5-2 times higher.
Content
Classification
According to the principle of action, glucometers are divided into photometric and electrochemical.
Photometric Glucometers
Determine the color change of the test zone, resulting from the reaction of glucose with special substances deposited on the strip. These are the so-called βfirst-generation devicesβ, the technology of which is already outdated. Note that such devices are calibrated with whole capillary blood.
Electrochemical glucometers
Glycemia indicators are measured in accordance with the magnitude of the current that appears during the reaction of blood glucose with special substances in the test strip (amperometry). These devices belong to the next generation, the technology of which allows minimizing the influence of external factors on the result and obtaining more accurate readings, especially over time. Most of these instruments have plasma calibration. It should be noted that in Russia, the majority of stationary devices of medical institutions evaluate peripheral blood glucose levels. There is another electrochemical method - coulometry. It consists in measuring the total charge of electrons released in the same process. Its advantage is the need for a very small amount of blood.
Optical glucose biosensors
The operation of optical biosensors is based on the phenomenon of surface plasmon resonance . Classical surface plasmon resonance biosensors are a sensor chip, one side of which is covered with a microscopic layer of gold. The use of such sensors for measuring glucose in the blood is not economically effective. Next-generation optical biosensors do not contain a thin metal layer, but spherical particles on the sensor surface, which increases sensitivity by more than 100 times and allows you to determine the concentration of sugar in human biological fluids (saliva, urine, sweat). This technology is under development, but shows promising results. The main difference of the technology is the complete non-invasiveness of glucose measurement [1] [2] .
Raman blood glucose meters
The Raman spectrum of the skin is measured and the amount of glucose is measured by isolating its spectrum from the full spectrum of the skin. This technology is under development, but shows promising results. The main difference of the technology is the complete non-invasiveness of the measurement [3] .
Glucometer Accuracy
Each glucometer has a measurement error range of 20% (according to ISO 15197), therefore, the results of measuring blood glucose on different devices and laboratories at the same time may differ slightly. It should also be borne in mind that in 5% of cases, the measurement error can exceed 20%. In addition, many modern glucometers show plasma glucose levels, which are 11-15% higher than laboratory data for capillary blood . To check the accuracy of glucometers, the βControl solutionβ is used. The control solution contains a fixed amount of glucose (LOW / low concentration - 0.05%, HIGH / high concentration - 0.3%), preservatives, red dye, and a thickening substance. It is significant that the method of assessing the quality of a glucometer using a control solution is not absolutely accurate, since in this case a single system "glucometer + strip" is tested; accordingly, the error can be determined both by the inaccuracy of the meter and the marriage of the test strip.
Accessories
The meter is not used as a single device, but is included in the set of self-monitoring tools for people with diabetes. Glucometers supplement semi-automatic finger piercing scarifiers (consumables: a set of disposable lancets), syringe pens (semi-automatic syringes for dosing and administering insulin) and a set of replaceable insulin cartridges. Currently, there are also disposable (non-rechargeable) syringe pens. To power the glucometers, specialized accumulators and batteries (batteries) are used. Blood glucose is measured using glucometers using disposable test strips.
As a rule, each manufacturer produces unique test strips for their glucometer, which are compatible only with a specific model of the glucometer of this manufacturer.
Links
Notes
- β Progress on detecting glucose levels in saliva . Brown University.
- β Biosensor for non-invasive glucometer (inaccessible link) . Rinno center. Date of treatment October 17, 2014. Archived October 3, 2014.
- β Raman spectroscopy for measurement of blood analytes . Massachusetts Institute of Technology. Date of treatment November 15, 2011. Archived February 22, 2012.