For some people, an even better option is the continuous glucose monitor, or CGM. This device uses a sensor that's inserted just beneath the skin to measure glucose levels that closely correlate with those in the blood. It delivers real-time readings every few minutes throughout the day and night. The readings are transmitted to a receiver (or compatible insulin pump), which can store them for a number of weeks. Charting spikes and drops, identifying high or low blood glucose triggers, and making lifestyle adjustments are easier with data from a continuous glucose monitor. CGMs are particularly useful for children and all those with type 1 diabetes.
Regardless of which method is best for you, it's important to realize that all monitors aren't created equal. And what works well for one person may not work for another. Read on to find out the five things you should do before you pick a meter.
- Do a test run. On paper, most blood glucose monitors look the same. So if you can, test them out before you buy. (Your diabetes educator should be stocked with sample monitors.) Most blood glucose monitors require a blood sample size of about 1 microliter--about the size of the tip of a ballpoint pen--for testing. Many meters even use a smaller sample size. Today's technology allows people to use small sample sizes and compute results in a matter of seconds. You'll want to determine how easy each is for you to use (some versions require more steps than others) and how quickly the monitor calculates a reading. Talk to your diabetes educator about your needs, and don't be afraid to ask around for advice. Friends and family members who have diabetes may be able to recommend a brand that works well for them.
- Determine the cost. In the end, the monitor itself won't be an astronomical expense; your insurance and company rebates may cover most or all of the cost. But that doesn't mean you're in the clear. Here's why: The onetime fee for a monitor is dwarfed by the cost of the test strips. Though their price may sound small (like $0.75 per strip), consider how many strips you'll be using each day, week--and year. Be aware that insurance companies vary in the amount of test strips they will cover per person per day. The cost adds up, but there are steps you can take to lower it. Find out, for example, if your health plan covers a specific monitor and test strip brand.
- Consider your test site. The most common place for a person with diabetes to draw a drop of blood is from the fingertip. If pricking your finger is too painful, consider choosing a monitor that allows alternate site testing. Some monitors let you test blood drawn from areas which may feel less pain, such as your palms, arms, or thighs. Keep in mind, however, the differences that may occur between testing sites. After a meal or when you're experiencing hypoglycemia, your glucose levels are changing rapidly. In these situations, you should always test blood from your fingertips, which will provide you with closer to real-time levels (the level of glucose in alternate sites is about 15 minutes behind). Testing from alternate sites is permissible when your glucose levels are stable--like before a meal--since results from a finger prick and alternate site test will be similar. But note: Not everyone is able to draw enough blood from alternate sites in order to test.
- Think about record-keeping. All monitors have a memory feature that keeps track of your past glucose readings. Many even summarize and compute data themselves. Some also work with special computer-based management programs. For the tech-savvy, these programs provide a way to store data, track your daily or weekly average glucose, view charts and graphs, and share information with your health care provider. While several monitor manufacturers charge for the software, others provide it for free. You may also want to ask your doctor if he or she has a program available in his or her office. If so, using your doctor's program during scheduled office visits may be cost-effective. But remember: Going digital doesn't mean you should necessarily scrap a written log if it's working for you.
- Take care of any visual or language needs. Successfully testing your blood glucose level can be difficult when you have impaired vision. Thankfully, certain monitors will talk to you, providing instructions for use as well as an audible test result. You can also ask your diabetes educator about models that speak instructions and display results in another language. You should also pay attention to how well you can read the numbers when shopping for a monitor (some are specifically designed for the visually impaired).
Once you've chosen a monitor, talk to your doctor or educator about maintaining its accuracy. While monitors generally have the same degree of accuracy, it's important to understand steps you should take to ensure your monitor remains accurate. For starters, you can bring your monitor with you to a doctor's appointment and check within a minute or two of having a blood sample drawn there. Your monitor's result and the one provided by your doctor's laboratory should be similar (within 15 percent or so) if your monitor provides what is called a "plasma glucose" reading, as virtually all newer meters are calibrated to do. Otherwise, ask your doctor or diabetes educator about how best to compare the readings.
Another means of checking your monitor's accuracy in regard to its test strips is by using a control solution once a month. The liquid--a starter bottle usually comes with your monitor but can also be purchased at the drugstore--will have a known glucose level. If your meter reads that level, you know your meter and test strips are working together properly. If the reading is incorrect, tell your doctor so that he or she can help you take steps to ensure your meter and strips are in agreement.
To keep your monitor functioning correctly, it's important to take care of it. An old or dirty monitor--or one that has been stored at extreme temperatures--may lead to inaccurate readings. Prevent this by learning the manufacturer's care instructions, working with your health care team to train on the monitor, and keeping supplies like test strips up to date and stored correctly. Skipping hand washing (if you test on your fingers) opens the door for errors. Prevent such inaccuracies by thoroughly cleaning your test site before using your monitor.
If your monitor requires you to enter a code number provided on your test strip package each time you open a new box, it's important that you follow the instructions. You may also be required to insert a code chip from your test strip bottle into the meter. Or you may be able to press a button on the meter to code. When a monitor is miscoded, the test strips and monitor can't properly communicate with each other, and that may lead to readings that are off by more than 40 percent. If coding sounds confusing and time consuming, consider purchasing a newer monitor that automatically codes.
To get a drop of blood onto your meter’s test strip, you'll need to prick your skin. Most people use an automatic lancing device, a spring-loaded tool containing needles that releases with the press of a button. There are various types of lancing devices--usually included in blood glucose monitoring kits--and most allow you to control the depth of penetration via adjustable settings. How you choose your lancing device will depend on a number of factors, such as ease of use, needle gauge, how well you are able to draw blood with it, whether or not the device minimizes pain, and if it allows for testing on alternate sites other than the finger, such as your palm, forearm, upper thigh, or calf.
Getting a sizeable drop of blood is difficult for some people, and if switching lancing devices doesn’t produce a big enough drop, you may need to prepare before you prick. Wash your hands with warm water or massage your fingers to increase blood flow. Once you've pierced your fingertip, lightly squeeze the finger to elicit blood.
The same precautions and care you take with your insulin needles apply to lancets, too. For starters, don't share your lancets or lancing device with anyone else; doing so can transmit diseases. Reusing your lancet is not recommended. A reused lancet is much duller than a new one, so you're more likely to feel pain. Plus, a reused lancet increases your risk of infection.