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 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.
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
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 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.
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 Ascensia Diabetes Care Holdings AG, and the Accu-Chek meter. 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. Prior to its discontinuation in July 2021, the YSI 2300 STAT PLUS Glucose and Lactate Analyzer was widely accepted as the de facto standard for reference measurements and system calibration by most manufacturers of glucometers for the past 30 years, despite there being no such regulatory requirement.
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%.
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.Test strip meters
There are several key characteristics of glucose meters which may differ from model to model:- Size: The typical size is smaller than the palm of the hand. They are battery-powered.
- Test strips: A consumable element, different for each meter, containing spots impregnated with glucose oxidase, which reacts with glucose, and other components. A drop of blood is absorbed by a spot for each measurement. Some models use single-use plastic test strips with a spot; other models use discs, drums, or cartridges with multiple spots to make several readings.
- 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 pricks that do not produce enough blood.
- Alternate site testing: Smaller drop volumes have enabled "alternate site testing" – pricking the forearms or other less sensitive areas instead of the fingertips. Manufacturers recommend that this type of testing should only be used when blood glucose levels are stable, such as before meals, when fasting, or just before going to sleep.
- Duration of test: The time it takes for a reading to be displayed may range from 3 to 60 seconds from application of blood for different models.
- Display: The glucose value in mg/dL or mmol/L is displayed on a digital display. Different countries use different measurement units: for example mg/dL are used in the US, France, Japan, Iran, Israel, and India; mmol/L are used in Australia, Canada, China, and the UK. In Germany both units are used. Many meters can display either unit of measure. Instances have been published in which a patient has interpreted a reading in mmol/L as a very low reading in mg/dL or vice versa. Usually mmol/L readings have a decimal point and mg/dL readings do not.
Countries that use mg/dL include Algeria, Argentina, Austria, Bangladesh, Belgium, Brazil, Chile, Columbia, Cyprus, Ecuador, Egypt, France, Georgia, Germany, Greece, India, Indonesia, Iran, Israel, Italy, Japan, Jordan, Korea, Lebanon, Mexico, Peru, Poland, Portugal, South Korea, Spain, Syria, Taiwan, Thailand, Tunisia, Turkey, United Arab Emirates, United States, Uruguay, Venezuela, and Yemen.
- Memory and timestamping: Most meters include a memory to store test results, timestamped by a clock set by the user, and many can display an average of recent readings. Stored data will only reflect trends accurately if the clock is set to approximately the right time.
Cost
Batches of counterfeit test strips for some meters were found in the United States, producing erratic test results that do not meet the legitimate manufacturer's performance specifications.