Blood Glucose Meters (Glucometers)
Blood glucose meters are used to perform self-monitoring of blood glucose levels in all individuals with diabetes. There are lots of different models of meters—also called blood glucose monitors or glucometers—but they all detect the level of sugar in your blood, and give you the results almost instantly.
How do blood glucose meters work?
First, you use a lancet to pierce your skin and apply a drop of blood to the meter’s test strip. Then a series of chemical reactions takes place between the sugar in your blood and substances on the test strip. The reaction is measured by the meter and converted into a digital number that displays on the screen.
How to Test Properly
Always read the instructions for your particular model, and ask for training from your healthcare professional. It’s possible to get an inaccurate reading if you don’t use your meter properly. Always start by washing your hands with soap and warm water. Dirt and residue on your skin can cause inaccurate results. Check to make sure your test strips are not expired. Also ensure that they have not been exposed to extreme temperatures. If your meter requires a code, make sure you’ve entered it properly. And be sure to test a big enough drop of blood – some meters can read falsely if there is not enough blood.
How do I know which product is right for me?
Talk with your pharmacist or diabetes educator to help make a choice that fits you and your lifestyle. Make sure your device allows you to perform regular blood glucose readings comfortably and easily.
Blood glucose meters have advanced significantly over the years, and many of the features on current devices make them very easy to use and trouble-free. There are several key features that vary from meter to meter.
The average size is approximately the size of the palm of the hand but many are even smaller. They may be battery-powered or re-chargeable.
Some models utilize a plastic test strip with a designated area to apply blood. Each strip is used once and then discarded. Other models use discs, drums, or cartridges that are capable of multiple tests before changing them.
Most current meters do not require coding. Some older 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. Incorrect coding can lead to meter errors or incorrect results.
Volume of blood sample
The size of the drop of blood needed by different models varies and can be as small as 0.3 microliters. Smaller volume requirements reduce the need for deep or mutiple fingers pokes.
Alternative site testing
Meters that have smaller drop volumes allow “alternate site testing” — pricking the forearms or other less sensitive areas instead of the fingertips. Although less painful, these readings are not accurate when blood glucose is changing rapidly such as after a meal or after exercise. Alternate site testing should only be use for pre-meal tests.
The times it takes to read a test strip may range from 3 to 60 seconds for different models.
In Canada, the glucose value in mmol/l is displayed on a digital display. The size of the screen and the availability of a backlight varies with each model.
Most meters include a memory feature to remember past test results. The memory is an important feature as it allows you to keep a record of your tests and look for trends and patterns in blood glucose levels over days and weeks. Ensure your clock on your meter is set to the correct time to so that the information is accurate.
Many meters now have sophisticated data handling capabilities. Most can be downloaded by to a computer that has diabetes management software or to webware. Some meters even allow you to add data throughout the day, such as insulin dose, amounts of carbohydrates eaten, or exercise.
The cost of home blood glucose monitoring can be substantial due to the cost of the test strips. Meters are often available at no charge from your diabetes education center or pharmacy. Test strips may be covered by your private insurance plan – talk to your pharmacist for assistance. The Alberta Monitoring for Health Program can help provide coverage for low income individuals or families.
Accuracy of glucose meters is a common topic of clinical concern. Blood glucose meters must meet accuracy standards set by the International Organization for Standardization (ISO). According to ISO 15197 Blood glucose meters must provide results that are within 20% of a laboratory standard 95% of the time. New standards approved internationally will push the accuracy requirement up to +/- 15%, so many meter manufacturers are developing new meters and strips to achieve these standards.