Four generations of blood glucose meter, c. 1993-2005. Sample sizes vary from 30 to 0.3 μl. Test times vary from 5 seconds to 2 minutes (modern meters are typically below 15 seconds).

A glucose meter (or glucometer) is a medical device for determining the approximate amount of glucose in a drop of blood obtained by pricking the skin with a lancet. Glucose meters are portable and designed for use by laypersons, including those with diabetes. Image File history File links Glucose_meters. ... Image File history File links Glucose_meters. ... // COUNCIL DIRECTIVE 93/42/EEC of 14 June 1993 concerning medical devices defines a ‘medical device’ as: any instrument, apparatus, appliance, material or other article, whether used alone or in combination, including the software necessary for its proper application intended by the manufacturer to be used for human beings for... Glucose (Glc), a monosaccharide (or simple sugar), is the most important carbohydrate in biology. ... Human blood smear: a - erythrocytes; b - neutrophil; c - eosinophil; d - lymphocyte. ... Lancet may refer to: A lancet is a medical instrument, similar to a scalpel but with a double-edged blade. ... This article is about the disease that features high blood sugar. ...

The glucose meter is a key element of home blood glucose monitoring (HBGM) by people with diabetes mellitus or with proneness to hypoglycemia. Since approximately 1980, a primary goal of the management of type 1 diabetes has been the achievement of closer-to-normal levels of glucose in the blood for as much of the time as possible, guided by HBGM several times a day. This has greatly increased the trouble and time spent in the daily care of this disease but has also reduced rates of long-term complications and improved the management of short-term, potentially life-threatening complications such as hypoglycemia. In medicine, blood sugar is glucose in the blood. ... For the disease characterized by excretion of large amounts of severely diluted urine, see diabetes insipidus. ... Hypoglycemia (hypoglycæmia in the UK) is a medical term referring to a pathologic state produced by a lower than normal amount of sugar (glucose) in the blood. ... See diabetes mellitus for further general information on diabetes. ... For the disease characterized by excretion of large amounts of severely diluted urine, see diabetes insipidus. ... Diabetic hypoglycemia describes low blood glucose (hypoglycemia) occurring in a person with diabetes mellitus. ...

Characteristics

There are now dozens of models of glucose meters. There are several key characteristics that may differ from model to model:

• Size: The average size is now approximately the size of the palm of the hand, though some are smaller or a bit larger. They are battery-powered.

• Test strips: A consumable element containing chemicals which react with glucose in the drop of blood is used for each measurement. For most models this element is a plastic test strip with a small spot impregnated with glucose oxidase and other components. Each strip can only be used once and is then discarded. Instead of individual strips, some models use discs that may be used for several readings.

• Coding: Since test strips may vary from batch to batch, some models require the user to enter in a code that may be found on the vial of test strips. By entering the code into the glucose meter, the meter will be calibrated to the batch of test strips. Some models may not require coding.

• Volume of blood sample: The size of the drop of blood needed by different models currently varies from 0.3 to 10 μl. Older models required larger blood samples, usually defined as a "hanging drop" from the fingertip. Smaller volume requirements reduce the frequency of unproductive pricks.

• Alternative site testing: Smaller drop volumes have enabled "alternate site testing"-- pricking the forearm or other less sensitive areas instead of the fingertips. Although less uncomfortable, readings obtained from forearm blood lag behind fingertip blood in reflecting rapidly changing glucose levels in the rest of the body.

• Testing times: The times it takes to read a test strip may range from 5 to 60 seconds for different models.

• Display: The glucose value in mg/dl or mmol/l displayed in a small window. The preferred measurement unit varies by country. Mg/dl are preferred in the US, mmol/l in Canada and Europe. To convert mmol/l of glucose to mg/dl, multiply by 18. To convert mg/dl of glucose to mmol/l, divide by 18 or multiply by 0.055. Many machines can toggle between both types of measurements and there have been a couple of published instances in which someone with diabetes has been misled into the wrong actions by assuming that a reading in mmol/l was really a very low reading in mg/dl, or the converse. Other machines are pre-set at the factory and cannot be changed.

• Whole Blood Glucose vs. Plasma Glucose: Glucose levels in plasma (one of the components of blood) are generally 10-15% higher than glucose measurements in whole blood (and even more after eating). This is important because home blood glucose meters measure the glucose in whole blood while most lab tests measure the glucose in plasma. Currently, there are many meters on the market that give results as "plasma equivalent", even though they are actually measuring whole blood glucose. The plasma equivalent is calculated from the whole blood glucose reading using an equation built into the glucose meter. This allows patients to easily compare their glucose measurements in a lab test and at home. It is important for you and your healthcare provider to know whether your meter gives its results as "whole blood equivalent" or "plasma equivalent."

• Clock/Memory: All meters now include a clock which must be set for date and time, and a memory for past test results. The memory is an important aspect of diabetes care, as it enables the person with diabetes to keep a record of management and look for trends and patterns in blood glucose levels over days. Most memory chips can display an average of recent glucose readings.

• Data transfer: Many meters now have more sophisticated data handling capabilities. Many can be downloaded by a cable or infrared to a computer which has diabetes management software to display the test results in a variety of formats. Some meters allow entry of additional data throughout the day, such as insulin dose, amounts of carbohydrates eaten, or exercise. A number of meters have been combined with other devices, such as insulin injection devices, PDAs, and even Game Boys^[1]. A radio link to an insulin pump allows automatic transfer of glucose readings to a calculator that assists the wearer in deciding on an appropriate insulin dose. One model also measures beta-hydroxybutyrate in the blood to detect ketoacidosis (ketosis).

• Hospital glucose meters: Special glucose meters for multi-patient hospital use are now used. These provide more elaborate quality control records, and the data handling capabilities are designed to transfer glucoses into electronic medical records and the laboratory computer systems for billing purposes.

This does not cite its references or sources. ... The glucose oxidase enzyme (GOx) (EC 1. ... Example 1: An electronic logbook that can collect and manage data from multiple sources Example 2: Data plots of blood glucose readings useful to analyze patterns and improve insulin delivery Example 3: Charts prepared to look for patterns and improve insulin delivery Example 4: A summary of a pumping day... Insulin (from Latin insula, island, as it is produced in the Islets of Langerhans in the pancreas) is a polypeptide hormone that regulates carbohydrate metabolism. ... Lactose is a disaccharide found in milk. ... palmOne Tungsten T5 (CDAs) are handheld devices that were originally designed as personal organizers, but became much more versatile over the years. ... For the entire Game Boy series of handheld consoles, see Game Boy line. ... Insulin Pump with an Infusion Set An insulin pump is a medical device used for administering insulin in the treatment of diabetes mellitus. ... Beta-hydroxybutyrate, acetoacetate, and acetone collectively are called ketone bodies. ... Ketosis (IPA pronunciation: ) was identified by Dr. Stephen Moody in 1969 and is a stage in metabolism occurring when the liver has been depleted of stored glycogen and switches to a chronic fasting mode during long periods of starvation. ... It has been suggested that this article or section be merged with Electronic health record. ... A medical laboratory or clinical laboratory is a laboratory where tests are done on biological specimens in order to get information about the health of a patient. ...

Cost

The cost of daily testing is one of the most expensive aspects of diabetes care. In 2006, the consumer cost of each glucose strip ranges from about $0.35 to 1.00 , so that testing 4 times a day costs about $3-4 a day for people with diabetes. Manufacturers often provide meters at no cost to induce use of the profitable test strips. Type 1 diabetics test as often as ten to twelve times a day due to the dynamics of insulin adjustment, whereas type 2 test less frequently, especially when insulin is not part of treatment. ISO 4217 Code USD User(s) the United States, the British Virgin Islands, East Timor, Ecuador, El Salvador, the Marshall Islands, Micronesia, Palau, Panama, Turks and Caicos Islands, and the insular areas of the United States Inflation 3. ... ISO 4217 Code USD User(s) the United States, the British Virgin Islands, East Timor, Ecuador, El Salvador, the Marshall Islands, Micronesia, Palau, Panama, Turks and Caicos Islands, and the insular areas of the United States Inflation 3. ...

Accuracy

Accuracy of glucose meters is a common topic of clinical concern. Nearly all of the meters have similar accuracy (±10-15%) when used optimally. However, a variety of factors can affect the accuracy of a test. Factors affecting accuracy of various meters have included calibration of meter, ambient temperature, pressure use to wipe off strip, size of blood sample, high levels of certain drugs in blood, hematocrit, dirt on meter, humidity, and aging of test strips. Models vary in their susceptibility to these factors, and in their ability to prevent or warn of inaccurate results with error messages. The Clarke error grid is a common way of analyzing and displaying accuracy of readings related to management consequences.

History

The earliest widely-used meter was the Ames Reflectance Meter, which was used in American hospitals in the 1970s. It was about 10 inches long and required connection to an electrical outlet for power. A moving needle indicated the blood glucose reading after 60 seconds.

Home glucose monitoring was demonstrated to improve glycemic control of type 1 diabetes in the late 1970s, and the first meters were marketed for home use around 1980. The 2 models initially dominant in North America in the 1980s were the Glucometer and the Accuchek meter, and to many nurses and other medical professionals these brand names became synonymous with the generic product (the Kleenex/Xerox phenomenon) and are still current in hospitals. To meet Wikipedias quality standards, this article or section may require cleanup. ... Unfolded tissue below a Kleenex pack. ... Xerox Corporation (NYSE: XRX) is an American document management company, which manufactures and sells a range of color and black-and-white printers, multifunction systems, photo copiers, digital production printing presses, and related consulting services and supplies. ...

Test strips that changed color and could be read "visually", without a meter, were also widely used in the 1980s. They had the added advantage that they could be cut with scissors longitudinally to save money. As meter accuracy and insurance coverage improved, they lost popularity and are no longer marketed.

At least in North America, hospitals resisted adoption of meter glucose measurements for inpatient diabetes care for over a decade. Managers of laboratories argued that the superior accuracy of a laboratory glucose measurement outweighed the advantage of immediate availability and made meter glucose measurements unacceptable for inpatient diabetes management. Patients with diabetes and their endocrinologists eventually persuaded acceptance. A physician visiting the sick in a hospital. ... A medical laboratory or clinical laboratory is a laboratory where tests are done on biological specimens in order to get information about the health of a patient. ... Endocrinology is a branch of medicine dealing with disorders of the endocrine system and its specific secretions called hormones. ...

Home glucose testing was adopted for type 2 diabetes more slowly than for type 1, and a large proportion of people with type 2 diabetes have never been instructed in home glucose testing. See diabetes mellitus for further general information on diabetes. ...

Future

Development of noninvasive devices may enable continuous monitoring. Currently, research is being done on noninvasive methods for measuring blood glucose, such as using electric currents and ultrasound. Currently, there is one noninvasive glucose meter that has been approved by the FDA. The GlucoWatch G2 Biographer is designed to be worn on the wrist, and it uses electric fields to draw out body fluid for testing. However, the device does not replace conventional blood glucose monitoring. The GlucoWatch system is not able to cope with perspiration at the measurement site. Many diabetics have nerve damage causing dietetic sweats. The sweat must be allowed to dry before measurement can resume. This page is a candidate for speedy deletion because: If you disagree with its speedy deletion, please explain why on its talk page or at Wikipedia:Speedy deletions. ...

It is speculated that within the next decade, meters may be replaced with continuous glucose sensors for many people with diabetes. This will likely decrease complications found in people with diabetes by limiting problems associated with hyperglycemia and hypoglycemia. Blood glucose monitoring is a way of testing how much glucose is in the blood. ...

The DexCom™ STS® System is currently available, (2Q 2006) It is a hypodermic probe with a small transmitter. The receiver is about the size of a cell phone and can operate up to 5 feet from the transmitter. Aside from a two hour calibration period, monitoring is logged at 5 minute intervals for up to 72 hours. High and low glucose alarms are user settable. Different bevels on hypodermic needles Syringe on left, hypodermic needle with attached color-coded luer lock on right. ...

Technology

So far all glucose meters have in some way employed the oxidation of glucose to gluconolactone catalyzed by glucose oxidase. Glucono delta-lactone (GDL) is a naturally occurring food additive used as a sequestrant, an acidifier, or a curing, pickling, or leavening agent. ... The glucose oxidase enzyme (GOx) (EC 1. ...

The first-generation devices relied on the same colorimetric reaction that is still used nowadays in glucose test strips for urine. Besides glucose oxidase, the test kit containes a benzidine derivative, which is oxidized to a blue polymer by the hydrogen peroxide formed in the oxidation reaction. The disadvantage of this method was that the test strip had to be developed after a precise interval (the blood had to be washed away), and the meter needed to be calibrated frequently. Colorimetry is the science that describes colors in numbers, or provides a physical color match using a variety of measurement instruments. ... Benzidine is the trival name for 4,4-diaminobiphenyl, this is a carcinogenic aromatic amine which has been used as part of a test for cyanide and also in the synthesis of dyes. ... Hydrogen peroxide (H2O2) is a very pale blue liquid which appears colourless in a dilute solution, slightly more viscous than water. ...

Today's glucometers use a coulometric method. Test strips contain a capillary that sucks up a reproducible amount of blood and an enzyme electrode containing glucose oxidase. The enzyme is reoxidized with an excess of ferrocyanide ion. The total charge passing through the electrode is measured and is proportional to the concentration of glucose in the blood. Coulometry is the name given to a group of electroanalytical chemistry techniques that determine the amount of matter transformed during an electrolysis reaction by measuring the amount of electricity (in coulombs) consumed or produced. ... The ferrocyanide ion is Fe(CN)64-. Using IUPAC nomenclature, this would be called hexacyanoferrate(II) ion, but the old name is most common. ...

Meter use for hypoglycemia

Although the apparent value of immediate measurement of blood glucose might seem to be higher for hypoglycemia than hyperglycemia, meters have been less useful. The primary problems are precision and ratio of false positive and negative results. An imprecision of ±15% is less of a problem for high glucose levels than low. There is little difference in the management of a glucose of 200 mg/dl compared with 260 (i.e., a "true" glucose of 230±15%), but the difference between 70 mg/dl and 55 (i.e., 67±15%) represents a more unsatisfactory uncertainty. The imprecision is compounded by the relative likelihoods of false positives and negatives in populations of people with diabetes and those without diabetes. People with type 1 diabetes usually have glucose levels above normal, often ranging from 40 to 500 mg/dl (2.2 to 28 mmol/l), and when a meter reading of 50 or 70 (2.8 to 3.9 mmol/l) is accompanied by their usual hypoglycemic symptoms, there is little uncertainty about the reading representing a "true positive" and little harm done if it is a "false positive." In contrast, people who do not have diabetes but periodically have hypoglycemic symptoms will have a much higher rate of false positives to true, and a meter is not accurate enough to base a diagnosis of hypoglycemia upon. A meter can occasionally be useful in the monitoring of severe types of hypoglycemia (e.g., congenital hyperinsulinism), to ensure that the average glucoses when fasting remain above 70 mg/dl (3.9 mmol/l). Hypoglycemia (hypoglycæmia in the UK) is a medical term referring to a pathologic state produced by a lower than normal amount of sugar (glucose) in the blood. ... Hyperglycemia or High Blood Sugar is a condition in which an excessive amount of glucose circulates in the blood plasma. ... Congenital hyperinsulinism is a medical term referring to a variety of congenital disorders in which hypoglycemia is caused by excessive insulin secretion. ...