glucose meter glucose meter a glucose meter, also referred to as a "glucometer", is a medical device for determining the approximate concentration of glucose in the blood. it can also be a strip of glucose paper dipped into a substance and measured to the glucose chart. it is a key element of glucose testing, including home blood glucose monitoring (hbgm) performed by people with diabetes mellitus or hypoglycemia. a small drop of blood, obtained from slightly piercing a fingertip with a lancet, is placed on a disposable test strip that the meter reads and uses to calculate the blood glucose level. the meter then displays the level in units of mg/dl or mmol/l. glucose meterfour 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 typically provide results in 5 seconds).purposemeasure concentration of glucose in the blood since approximately 1980, a primary goal of the management of type 1 diabetes and type 2 diabetes mellitus has been achieving closer-to-normal levels of glucose in the blood for as much of the time as possible, guided by hbgm several times a day. the benefits include a reduction in the occurrence rate and severity of long-term complications from hyperglycemia as well as a reduction in the short-term, potentially life-threatening complications of hypoglycemia. history leland clark presented his first paper about the oxygen electrode, later named the clark electrode, on 15 april 1956, at a meeting of the american society for artificial organs during the annual meetings of the federated societies for experimental biology. in 1962, clark and ann lyons from the cincinnati children's hospital developed the first glucose enzyme electrode. this biosensor was based on a thin layer of glucose oxidase (gox) on an oxygen electrode. thus, the readout was the amount of oxygen consumed by gox during the enzymatic reaction with the substrate glucose. this publication became one of the most often cited papers in life sciences. due to this work he is considered the “father of biosensors,” especially with respect to the glucose sensing for diabetes patients. cdc image showing the usage of a lancet and a blood glucose meter another early glucose meter was the ames reflectance meter by anton h. clemens. it was used in american hospitals in the 1970s. a moving needle indicated the blood glucose after about a minute. 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 1981. the two models initially dominant in north america in the 1980s were the glucometer, introduced in november 1981, whose trademark is owned by bayer, and the accu-chek meter (by roche). consequently, these brand names have become synonymous with the generic product to many health care professionals. in britain, a health care professional or a patient may refer to "taking a bm": "mrs x's bm is 5", etc. bm stands for boehringer mannheim, now part of roche, who produce test strips called 'bm-test' for use in a meter. 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. 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. this has mainly come about because health authorities are reluctant to bear the cost of the test strips and lancets. non-meter test strips test strips that changed color and could be read visually, without a meter, have been widely used since the 1980s. they had the added advantage that they could be cut longitudinally to save money. critics argued that test strips read by eye are not as accurate or convenient as meter testing. the manufacturer cited studies that show the product is just as effective despite not giving an answer to one decimal place, something they argue is unnecessary for control of blood sugar. this debate also happened in germany where "glucoflex-r" was an established strip for type 2 diabetes. as meter accuracy and insurance coverage improved, they lost popularity. "glucoflex-r" is australia manufacturer national diagnostic products alternative to the bm test strip. it has versions that can be used either in a meter or read visually. it is also marketed under the brand name betachek. on may 1, 2009, the uk distributor ambe medical group reduced the price of their "glucoflex-r" test strip to the nhs, by approximately 50%. this was expected to allow the nhs to save money on strips and perhaps loosen the restrictions on supply a little. another low cost visually read strip is soon to be available on prescription according to sources at the nhs. types of meters hospital glucose meters special glucose meters for multi-patient hospital use are now used. these provide more elaborate quality control records. their data handling capabilities are designed to transfer glucose results into electronic medical records and the laboratory computer systems for billing purposes. blood testing with meters using test strips illustration depicting glucose monitoring with glucometer illustration depicting glucose meter and test strips there are several key characteristics of glucose meters which may differ from model to model: size: the average size is now approximately the size of the palm of the hand, although hospital meters can be the size of a remote control. they are battery-powered. test strips: a consumable element containing chemicals that react with glucose in the drop of blood is used for each measurement. for some models this element is a plastic test strip with a small spot impregnated with glucose oxidase and other components. each strip is used once and then discarded. instead of strips, some models use discs, drums, or cartridges that contain the consumable material for multiple tests. coding: since test strips may vary from batch to batch, some models require the user to manually enter in a code found on the vial of test strips or on a chip that comes with the test strip. by entering the coding or chip into the glucose meter, the meter will be calibrated to that batch of test strips. however, if this process is carried out incorrectly, the meter reading can be up to 4 mmol/l (72 mg/dl) inaccurate. the implications of an incorrectly coded meter can be serious for patients actively managing their diabetes. this may place patients at increased risk of hypoglycemia. alternatively, some test strips contain the code information in the strip; others have a microchip in the vial of strips that can be inserted into the meter. these last two methods reduce the possibility of user error. one touch has standardized their test strips around a single code number, so that, once set, there is no need to further change the code in their older meters, and in some of their newer meters, there is no way to change the code. volume of blood sample: the size of the drop of blood needed by different models varies from 0.3 to 1 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. alternate site testing: smaller drop volumes have enabled "alternate site testing" – pricking the forearms or other less sensitive areas instead of the fingertips. this type of testing should only be used when blood glucose levels are stable, such as when before meals, when fasting, or just before going to sleep. testing times: the times it takes to read a test strip may range from 3 to 60 seconds for different models. display: the glucose value in mg/dl or mmol/l is displayed on a digital display. the preferred measurement unit varies by country: mg/dl are preferred in the us, france, japan, israel, and india. mmol/l are used in canada, australia and china. germany is the only country where medical professionals routinely operate in both units of measure. (to convert mmol/l to mg/dl, multiply by 18. to convert mg/dl to mmol/l, divide by 18.) many meters can display either unit of measure; there have been a couple of published instances in which someone with diabetes has been misled into the wrong action by assuming that a reading in mmol/l was really a very low reading in mg/dl, or the converse. in general, if a value is presented with a decimal point, it is in mmol/l, without a decimal it is most likely mg/dl. table of blood glucose units of measurement by country country unit of measurement used country unit of measurement used algeria mg/dl malaysia mmol/l argentina mg/dl malta mmol/l australia mmol/l mexico mg/dl austria mg/dl netherlands mmol/l bahrain mg/dl new zealand mmol/l bangladesh mg/dl norway mmol/l belgium mg/dl oman mg/dl brazil mg/dl peru mg/dl canada mmol/l philippines mg/dl caribbean countries mg/dl poland mg/dl chile mg/dl portugal mg/dl china mmol/l qatar mmol/l colombia mg/dl russia mmol/l czech republic mmol/l saudi arabia mg/dl denmark mmol/l singapore mmol/l ecuador mg/dl slovakia mmol/l egypt mg/dl south africa mmol/l finland mmol/l spain mg/dl france mg/dl sub-saharan africa mg/dlmmol/l georgia mg/dl sweden mmol/l germany mg/dlmmol/l switzerland mmol/l greece mg/dl syria mg/dl hong kong mmol/l taiwan mg/dl india mg/dl thailand mg/dl indonesia mg/dl tunisia mg/dl ireland mmol/l turkey mg/dl israel mg/dl ukraine mmol/l italy mg/dl united arab emirates (uae) mg/dl japan mg/dl united kingdom mmol/l jordan mg/dl united states mg/dl kazakhstan mmol/l uruguay mg/dl korea mg/dl venezuela mg/dl kuwait mg/dl vietnam mmol/l lebanon mg/dl yemen mg/dl luxembourg mg/dl glucose vs. plasma glucose: glucose levels in plasma (one of the components of blood) are higher than glucose measurements in whole blood; the difference is about 11% when the hematocrit is normal. 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 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 patients and their health care providers to know whether the meter gives its results as "whole blood equivalent" or "plasma equivalent." one model measures beta-hydroxybutyrate in the blood to detect ketosis for measuring both unhealthy ketoacidosis and healthy nutritional ketosis. clock/memory: most meters now include a clock that is set by the user 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 and weeks. most memory chips can display an average of recent glucose readings. a known deficiency of all current meters is that the clock is often not set to the correct time (i.e., due to time changes, static electricity, etc.) and therefore has the potential to misrepresent the time of the past test results making pattern management difficult. data transfer: many meters now have more sophisticated data handling capabilities. many can be downloaded by a cable or infrared to a computer that has diabetes management software to display the test results. some meters allow data transfer to smartphones using bluetooth technology, where an app can be used to monitor readings over time. 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, cellular transmitters, and game boys. 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. cost the cost of home blood glucose monitoring can be substantial due to the cost of the test strips. in 2006, the consumer cost of each glucose strip ranged from about $0.35 to