High blood glucose levels are associated with significant complications of diabetes. These include cardiovascular disease, kidney and nerve damage. Alternatively, low blood glucose levels can cause acute symptoms of central nervous system impairment, such as confusion, seizures and more rarely coma and death. Self-blood glucose monitoring is a useful tool to personally manage blood glucose levels daily. It can help in the planning of meal times, exercise and determining the best time to take medications. A blood glucose monitor is an electronic device that detects glucose in blood samples using a test strip.
Blood Sampling
For a glucose test, blood is taken with a small lancet from the finger or less often another site. An article in the journal Diabetes Technology and Therapeutics reports that some glucose monitors require less than one microliter of blood. The tiny blood drop is collected onto a test strip, which has been inserted into the glucose monitor.
Test Strip Actions
The test strip contains an enzyme that oxidizes glucose to gluconolactone. In this oxidation reaction, electrons from glucose are transferred to another chemical. This reduced chemical transfers the electrons to either another indicator compound that forms a color or to an electrode, creating an electrical current.
Photometric Detection
If the monitor is photometric, it applies a particular wavelength of light to the colored compound on the test strip. The colored compound absorbs some of the light and reflects the rest. The glucose monitor detects the amount of reflected light. The amount of reflected light is inversely proportional to the glucose concentration in the blood sample.
Electrochemical Detection
If the monitor detects glucose electrochemically, it quantifies the amount of generated electrons that are transferred to an electrode. The glucose monitor detects the strength of the electrical current in amps, which is proportional to the glucose concentration in the blood sample.
Accuracy
A review of blood glucose meters in the January 2010 issue of Diabetes Forecast states that glucose monitoring devices are required under an international standard to produce results within a 20 percent margin of error. However, the Food and Drug Administration is advocating tougher standards. To improve the accuracy of self-blood glucose monitoring, the American Diabetes Association says to perform blood sampling on clean surface areas of the skin, use a clean meter, to not use out-of-date or improperly stored test strips and to regularly calibrate the device with test solutions of glucose.
New Technology
Multiple advances are taking place in the manufacturing of glucose monitors. New generation glucose monitors will have additional capabilities, including continuous monitoring, wireless communication, memory and sophisticated data management software that tracks glucose concentration trends over time. Glucose monitors will be able to detect glucose by other methods than blood sampling.
