Blood glucose (sugar) levels are continuously rising and falling throughout the day. People who have diabetes have to measure their blood sugar levels throughout the day, especially before they eat or exercise.
When you eat, blood sugar levels go up. When you exercise, blood sugar levels go down. In people without diabetes, the body is equipped to deal with these changes. The pancreas releases:
- insulin that helps sugar enter cells to be used for energy and store extra sugar in the liver
- glucagon that unlocks sugar from the liver for use when blood sugar level is low.
People with diabetes must balance their blood sugar because their pancreas does not release enough insulin or their insulin is inefficient. They take insulin to best mimic the body’s natural insulin action, paying attention to meals and physical activity; and ensuring blood sugar levels do not get too high or too low.
Blood sugar meters
Since the 1980s, people with diabetes have been able to check their blood sugar levels at home. The most common way to do home checking is with a blood sugar meter.
To measure blood sugar levels, meters need a droplet of blood from a finger prick. Some sugar meters will allow the droplet of blood to come from another site, such as the forearm or toes. However, the most accurate way to check blood sugar levels is using blood drawn from the fingertips. A small droplet of blood is applied to a test strip, which is inserted into the blood sugar meter. When used correctly, the meter provides a quick reading.
Lancing devices and lancets
To draw blood quickly and fairly painlessly, patients use lancing devices. Lancing devices are hand-held tools that, at the touch of a button, firmly push a tiny disposable needle (the lancet) into the skin to get the droplet of blood.
The needle tips on the lancet come in different sizes or gauges; the higher the gauge, the finer the needle. Even young children may be able to take their own blood samples, usually with adult supervision.
To avoid spreading infections, your lancing device should not be used on anyone else. It is recommended to change the lancet for every test.
Choosing a blood sugar meter
Many brands of blood sugar meters are available. When you get a blood sugar meter, there are a number of factors to consider, such as:
- recommendations from your diabetes team
- size of the meter and whether it is easy to take to school or other places
- amount of blood needed to get a reliable test result
- features you may prefer to have (for example, pattern recognition, alerts, or dose calculations)
- whether the results can be downloaded to a computer
- visibility of the results for children or caregivers.
Most blood sugar meters come as a kit. The kits typically will include a lancing device, lancets, a few test strips, and a carrying case. Extra lancets and test strips must be purchased separately.
How to use a blood sugar meter
How to test your blood sugar levels at home
Testing blood sugar levels at home is fairly easy and with practice, you and your child will soon become experts. You will need:
- the lancing device
- a new lancet
- a test strip.
Your child should wash their hands first and dry them well. Insert the lancet into the lancet device and insert a test strip into the blood sugar meter. Hold the device against one of your child’s fingers and push the trigger button. The lancet will quickly penetrate your child’s skin.
Gently milk your child’s finger from the base to the tip until a drop of blood forms. Repeat until you have enough blood to blot the strip.
Place the blood drop onto the test strip and wait for the results to appear on the meter screen. Be sure to record the reading into your child’s log book, and clean up any excess blood with a cotton swab.
Discard the used lancet into the sharps disposal container.
It is important to rotate fingers to ensure that a hard skin does not develop on any one finger. This can make future testing painful.
Making sure the reading is accurate: checking and calibration
If you are concerned about the accuracy of the blood sugar meter, have your home results checked against laboratory results. Results of the home blood sugar meter test should be within 20 per cent of the lab test. For example, if the lab reading is 10 mmol/L, the meter result should be between 8 and 12 mmol/L. A member of your health-care team can make sure that your meter test and lab test fall within the same range.
For most blood sugar meters you can purchase a control solution. It will help ensure that the test strips and blood sugar meter are giving accurate results.