Blood Glucose Monitors

Blood glucose monitors are devices that measure blood glucose levels electronically. They are indicated for individuals with diabetes mellitus type 1 or 2.In December 2016, the FDA expanded its approval of the Dexcom G5 Mobile Continuous Glucose Monitoring System (CGM) system as a replacement for traditional fingerstick testing in adults and children aged 2 years or older. This was the first CGM system that can be used for diabetes-related treatment decisions without use of a traditional fingerstick test for confirmation. ^{[1, 2]}

Since the initial introduction, many different devices have become available with variable accuracy and reliability of results. ^[3]  Whereas many devices are available with prescription coverage, others may be pruchased over the counter or from online sources. Some devices utilize nanoparticle sensors to determine the physiological range as a tool for real-time glucose tracking. ^[4]  One example is the FreeStyle Libre which came on the market in 2017. Another sensor patch technology is the Dexcom G6 which can be linked via an app to some insulin pumps. This technology uses interstitial fluids instead of blood to measure blood glucose.CGM technology is underprescribed and, if better utilized, could provide better hemoglobin A1c (HbA1c) control and decrease the incidence of diabetic complications. CGM is very helpful for patients with hypoglycemia unawareness and nocturnal hypoglycemia.

Design

Blood glucose meters measure blood glucose levels electronically. Some devices utilize only a small drop of blood from the fingertip placed on a disposable test strip. The digital meter obtains information from the blood on the strip, and within seconds, the glucose level is displayed on the screen. Other models use interstitial fluids to measure blood glucose. Patient discomfort and inconvenience are minimal, and compliance with testing regimens is therefore high. These devices collect data every 5 to 15 minutes. If the glucose level drops too low or rises too high, a preset alarm can sound.

Continuous blood glucose monitors

A continuous blood glucose monitor (CGM) assesses blood glucose levels on a near-continuous basis. A typical system consists of a glucose sensor placed subcutaneously, a non-implanted transmitter, and a receiver worn like a pager, which records blood glucose levels at frequent intervals and monitors trends. Newer devices have apps which can be linked to insulim pumps for real time adjustments. Newer devices may use a sensor that does not penetrate the skin.

CGM systems monitor interstitial fluid glucose levels. They must be calibrated with traditional fingerstick tests.

Continuous monitoring provides documentation of blood glucose response to insulin dosing, eating, exercise, and additional influences. Overnight monitoring may identify problems with insulin dosing and allow adjustments of basal levels. Many units are equipped with alarms to warn patients of hyperglycemia or hypoglycemia and provide time for treatment.

Blood glucose monitors are devices that measure blood glucose levels electronically. These units vary on price, size, ease of use, complexity of formatting, size of text, information sharing, and insurance coverage.

Category

Blood glucose monitors

Device details

Dozens of blood glucose monitors are commercially available. The following examples do not represent an all-inclusive list and are in no specific order. More than 160 commercially available devices are available. Some are Food and Drug Administration (FDA) cleared and pass both ISO 15197 2003 and ISO 15197 2013 standards, and some are not. ^[5]

• Roche Diagnostics - ACCU-CHEK
• Nova Biomedical - Nova Max Plus, Nova Max Link
• Abbott Diabetes Care - Precision Xtra, FreeStyle Lite, FreeStyle Freedom Lite
• LifeScan - OneTouch
• Nipro Diagnostics - TRUE2go, TRUEresult, TRUEtrack
• Diagnostic Devices - Prodigy
• Diabetic Supply of Suncoast - Advocate
• Arkray - GLUCOCARD
• Care Touch Blood Glucose Monitoring System
• FreeStyle Libre
• Dexcom G6
• Eversense
• Guardian Connect System

Blood glucose meters measure blood glucose levels electronically. Such measurement utilizes only a small drop of blood from the fingertip placed on a disposable test strip. The digital meter obtains information from the blood on the strip, and within seconds, the glucose level is displayed on the screen. Patient discomfort and inconvenience are minimal, and compliance with testing regimens is therefore high. There is a recurring cost to using blood glucose meters and disposable strips or sensors, but it is outweighed by the costs related to complications of diabetes.

Alternate-site testing uses the same meter and strip but acquires blood from the palm or the forearm. Thus, it causes virtually no pain and allows patients to rest sore fingertips. The disadvantage of alternate-site testing is that decreased blood flow may be encountered and may affect testing accuracy.

Multitest systems are available that utilize a cartridge or a disk with multiple test strips. These systems may be more convenient for patients.

Newer systems utilize a sensor that can be applied to the arm or abdomen and determine glucose levels from interstitial fluids. These do not require any blood. The transmit their data to the app on a patients phone for interpretation.

Many meters allow patients to download results to a computer so that they can be shared with their health care provider; this has the potential to improve diabetes management.

iBGStar (Sanofi) was the first blood glucose meter to connect directly to iPhone and iPod Touch. It uses the iBGStar Diabetes Manager application for recording, tracking, managing, and sharing blood glucose data. Recent research has shown good interassay and high intra-assay precision using the device. ^[6]

Continuous blood glucose monitors

A continuous blood glucose monitor (CGM) assesses blood glucose levels on a near-continuous basis. A typical system consists of a glucose sensor placed subcutaneously, a nonimplanted transmitter, and a receiver worn like a pager, which records blood glucose levels at frequent intervals and monitors trends.

CGM systems monitor interstitial fluid glucose levels. They must be calibrated with traditional fingerstick tests. Before treatment of reported hypoglycemia or hyperglycemia with insulin, confirmation with a fingerstick test is recommended because of the 5- to 15-minute lag in data reporting.

Continuous monitoring provides documentation of blood glucose response to insulin dosing, eating, exercise, and additional influences. Overnight monitoring may identify problems with insulin dosing and allow adjustments of basal levels. Many units are equipped with alarms to warn patients of hyperglycemia or hypoglycemia and provide time for treatment. Studies have demonstrated that patients using CGMs experience fewer hyperglycemic episodes and may decrease their glycated hemoglobin (HbA1C) levels. ^{[7, 8, 9]}

One recent concern, however, is proper calibration and availability of control solutions at pharmacies and appropriate use by patients during calibration. Lack of adherence to proscribed methodologies of use may lead to erroneous data and thus possible mistreatment of diabetes by patients. ^[10] Future development and technological advancements aim to allow for improved sensors and calibration software, creating better systems designed to automate delivery of insulin partially (eg, low glucose suspend) or entirely (eg, “fully closed-loop” artificial pancreas). ^{[3, 5, 11]}

Blood glucose monitors are indicated in individuals with diabetes mellitus type 1 or 2. CGM is not currently approved in pregnant patients, critically ill patients, and patients on dialysis. ^[12]

There is extensive evidence demonstrating the utility of blood glucose testing in persons with diabetes, especially those using insulin. Patients with diabetes who use insulin typically test their blood sugar more often (3-10 times per day) to assess the effectiveness of the previous dose and to determine the next dose.

Blood glucose monitoring allows patients to understand patterns of blood glucose changes and to adjust diet, exercise, and medication dosing. The significance of the optimal frequency of monitoring has yet to be clearly elucidated in patients with diabetes mellitus type 2, but experts suggest better control results in better outcomes. The clinical use of monitors resulted in fewer costly emergency room visits and hospitalizations for hypoglycemia and reduced rates of complications.

Health care providers should follow standard protocols for monitoring blood glucose levels. Information gathered from blood glucose monitors and glycated hemoglobin (HbA1C) levels may help guide management of patients with diabetes. Monitoring of patients with newly diagnosed diabetes may also help patients achieve a better understanding of their disease.

Complications of using blood glucose monitors include pain and soreness caused by the testing prick. Use of sensors on the skin may result in some sensitivites to the adhesive and require rotation of the location of sensor application.