Chapter 7
Checking Your Blood Glucose
IN THIS CHAPTER
Getting the scoop on checking your blood glucose
Surveying the types of blood glucose meters
Keeping tabs on your numbers
Checking your blood glucose is essential for managing diabetes. It helps you gauge your body’s reaction to medications, food, exercise, stress, sickness, and more. You’ll use this information in your daily life, and you’ll share this information with your healthcare provider to evaluate how things are going at checkups.
A blood glucose check is a snapshot of your blood glucose level that you can do anytime, anywhere. It’s separate from the A1C test used in the doctor’s office to diagnose diabetes or to measure your average blood glucose.
If you’re newly diagnosed, checking your blood glucose might be the first skill you learn. It may seem foreign at first, but be patient. You’ll get the hang of it. Checking blood glucose has never been easier or faster; we walk you through the steps in this chapter.
When and how often you check your blood glucose is highly individual. It depends on your goals, medications, and health. However, the American Diabetes Association has recommended guidelines, which we include in this chapter.
Checking your blood glucose also means doing something with that important information. We’ve got you covered. At the end of the chapter, we offer tips for tracking the data and explain what to do with it.
Why, When, and How to Check Your Blood Glucose Level
Your blood glucose level tells you about your body, and many factors can affect the numbers. If you’re stressed or sick, or you forget to take your medication, your numbers may be high. If you don’t eat enough or exercise for a long time, your numbers may be low. Strive to have your before-meal blood glucose number in the 80–130 mg/dL range and below 180 mg/dL 1–2 hours after meals.
Knowing your numbers helps you feel better in the short term and helps you prevent complications down the road. This section explains the ins and outs of checking your blood glucose level.
Knowing when to check your glucose level
When you’re first diagnosed with diabetes, you may feel like it’s annoying to check your blood glucose. It’s not uncommon for newbies to be overwhelmed or intimidated. The good news is that it gets easier with practice.
Talk with your doctor about how often and when to check your blood glucose. Before a meal or 2 hours after a meal are common times, but it’s really up to you and your healthcare provider. The timing of the checks isn’t set in stone. Instead, it’s based on your goals, lifestyle, health, and medications.
Some people may need to check their blood glucose in the mornings or late at night because they tend to have high or low blood glucose at those times. If you’re wondering how certain foods or types of exercise affect your blood glucose, you could check after you eat or work out.
If you use multiple daily injections of insulin, you’ll need to check before and often after every meal to see how food affects your blood glucose. Check when you wake up to make sure your blood glucose is in your target range to start the day. Check before and after exercise to know whether you need to eat something to balance the calories you burned.
Occasionally you’ll need to check your glucose levels at other times. If you’re sick or recovering from an illness, your blood glucose may be high (above 180 mg/dL or your individual target) or low (below 70 mg/dL), so you’ll need to keep an eye on it.
If you take oral medications or long-acting insulin, ask your healthcare provider when and how often to check your blood glucose. If you take multiple daily injections of insulin, you’ll check more often, so ask about those specifics, too.
Checking your blood glucose in a snap
Blood isn’t something most people think about or deal with very often. However, after you’re diagnosed with diabetes, that changes. You have to prick your finger to check your blood glucose levels. In time, you’ll be an expert and do it without even thinking about it. Some people are uncomfortable checking blood glucose in public, but there is no reason to be, and it can take as little as 15–20 seconds.
You use a blood glucose meter to check your glucose level (we cover glucose meters in the following section). Here are the steps to check your blood glucose:
- Wash and dry your hands.
- Insert a test strip into your meter.
- Use a lancing device to prick the side of your finger and draw a small sample of blood.
- Hold your finger to the test strip.
- Wait for the reading.
- Once it displays, record the reading or use it to take action.
Replace your lancet as necessary to keep the tip from getting dull and to make pricks more comfortable. (Find out more about lancets in the “Looking at lancets and test strips” section, later in the chapter.)
Eyeing your blood glucose targets
Together, you and your healthcare provider will figure out target ranges for blood glucose based on your goals. Targets are based on how long you’ve had diabetes, your age, complications, and other individual considerations.
The American Diabetes Association recommends these targets for most non-pregnant adults:
- A1C: Less than 7
- Before a meal: 80–130 mg/dL
- After a meal (1–2 hours after beginning a meal): Less than 180 mg/dL
However, different targets may be better for certain individuals. If you’re a senior, your doctor may say you don’t need to worry as much about keeping blood glucose in that tight range. If you’re pregnant, you’ll have different goals so you can keep the baby as healthy as can be (see more in Chapter 9).
Blood Glucose Meters and Accessories
Use a small, portable device called a blood glucose meter to measure the amount of glucose in your blood.
Think about your needs and do some research before you select a meter. For example, some meters may benefit people with limited vision or dexterity issues, or you may want the latest technology. Test strips go hand-in-hand with meters, so consider them as well. A meter that may be very low cost or free through a promotion may use more expensive test strips, and cost a lot in the long run. Select among certain meters based on your health insurance coverage. We give you an overview of meters, their features, and test strips in this section.
Checking out types of meters
Blood glucose meters have come a long way since they were first invented, but they all have the same basic parts.
Each device has a small slot where you insert a test strip. You take your test strip out of its container (a vial or package) and pop it in the slot. You prick your finger with a lancet to produce a drop of blood, and the test strip has chemicals that react with your blood glucose to give a reading.
You view the results of your blood test on a digital screen. A reading will appear as number (say, 100), followed by mg/dL (milligrams per deciliter). The number represents the amount of glucose in your blood.
Today you can find dozens of meters with all sorts of bells and whistles. But before you start drooling over all the latest features, you have to choose the type of device that works best for you. Luckily, they fall into two main categories: standard blood glucose meters and continuous glucose meters.
Standard blood glucose meters
A standard blood glucose meter reads your blood glucose in one moment. It’s just a snapshot. Prick, drop, and — voilà! — there it is. A standard blood glucose meter is what almost everyone with diabetes uses to check their blood glucose.
Continuous glucose meters
A continuous glucose meter (CGM) takes continuous readings of glucose levels in real time, rather than providing a snapshot. You wear the device all the time, although you change the sensor every few days depending on the brand and type.
A CGM has three parts: sensor, transmitter, and receiver.
You insert the sensor under your skin to monitor your interstitial fluid, which correlates to blood glucose. The sensor readings are wirelessly transmitted to a handheld receiver. The receiver displays blood glucose levels in real time and includes past readings.
The beauty and elegance of a CGM is that you can see blood glucose trends over time — whether you’re trending up or down. The receiver displays graphs and arrows pointing up or down.
Use these trends to make decisions about insulin or food. A CGM can also alert you to a high or low. You may choose to share these real-time readings with your doctor or family members so they can help monitor your health. Some CGMs are designed to work with meters and insulin pumps to streamline use.
Check with your insurance provider about coverage for CGMs, which are more likely to be covered for people who have type 1 diabetes.
Being aware of meter accuracy
The U.S. Food and Drug Administration (FDA) has established guidelines regarding the accuracy of blood glucose meters. Because millions of people use and rely on these devices, it’s important that they give the most accurate readings possible.
Manufacturers are now required to clearly state the accuracy of their meters on the outside of boxes and test strips. These are shown as percentages (95 percent accuracy, for example). This data will help you buy a better, more accurate meter.
A more accurate meter will lead you to make correct decisions about controlling your diabetes. If a meter shows inaccurate results, you may take an incorrect action that could have serious consequences. Bottom line: Pay attention to meter accuracy.
The FDA has these recommendations for testing your meter’s performance:
- Some meters use a liquid control solution (containing a known amount of glucose). Use the control solution in place of a blood sample to see whether the results match the range listed on your test strips. An unusual number could mean you have a problem with your meter or your test strips.
- Your meter also runs its own electronic check each time it’s turned on so keep an eye out for error codes and consult your instructions if you see one.
- Bring your meter with you for your next checkup. Show your provider your technique and measure your meter’s reading with a laboratory blood test.
Considering a multitude of meter features
As technology advances, so do the features you can find in blood glucose meters. You can find basic meters that do nothing more than measure your glucose level and save your numbers. On the other end of the spectrum, you can find meters that calculate your mealtime insulin dose, have a backlit screen for testing in the dark, and work with your smartphone. How fancy a meter you want is up to you.
The following lists include some options to consider if you have special circumstances.
If you have vision problems:
- A high-contrast screen makes readings easier to see.
- Audio features such as a talking meter may help.
- A backlight could make readings easier to see, especially at night.
- Port lights help you insert test strips and take readings at night.
If dexterity is a challenge:
- Larger meters are easier to grip.
- Larger test strips with easy-to-grasp containers could help.
If you like using the latest technology, most meters allow you to download readings that detail the date, time, result, and other information to a software program on your computer or other device. Some meters wirelessly transmit readings to your smartphone or the cloud (using Wi-Fi or Bluetooth).
In addition to measuring your glucose level, some meters measure blood pressure or ketones. (We explain the importance of these measures in Chapter 8.)
Other meters offer access to certified diabetes educators (CDEs) and advice. A meter that includes a bolus calculator (a feature that tells you how much insulin is needed at mealtime) is a plus for people on intensive insulin therapy. Finally, you may want a meter that lets you test in other areas of your body, such as your arms or thighs, if you get calluses on your fingertips that make them hard to prick.
Minding money matters
Because blood glucose meters offer many different features and designs, they’re available at a wide range of price points. You’re guaranteed to find one that fits your budget.
Devices range in cost from $10 or so to $150. However, don’t think you have to spend a bundle on a blood glucose meter. You can buy a decent one for around $20.
Your healthcare provider will give you a prescription for the meter, test strips, and lancets. These tools are also available over the counter. However, having prescriptions for your health insurance or Medicare can help cover the costs.
Do your homework. Your health insurance or Medicare may cover only certain meters and test strips. What if your healthcare provider prescribes a meter that isn’t covered? Ask him to write a letter to your health insurer to obtain coverage, or ask him whether you can change meters and use one that is covered by your insurance.
Medicare Part B covers the cost of meters, test strips, lancet devices, and lancets. You can buy testing supplies through Medicare’s National Mail-Order Program for delivery to your home or from any local pharmacy or store that’s enrolled with Medicare.
Not only do you have to consider the meter’s cost, but you also have to think about how much the test strips will cost you on a monthly or yearly basis. In the long run, your meter’s test strips will cost you much more than the meter itself.
If you don’t have insurance or you’re having trouble affording your test strips, you have some options. Some strip manufacturers offer assistance programs, and some governmental and local groups may offer discounted supplies. Ask your healthcare provider or pharmacist about these programs.
You might also consider switching to generic, instead of brand name, meter and strips, such as those sold by CVS, Rite Aid, Target, Walgreens, and Walmart.
Every year, the American Diabetes Association’s magazine, Diabetes Forecast, publishes a consumer guide to blood glucose meters and other products. You can read the consumer guide with a print subscription or access it online at www.diabetesforecast.org.
Looking at lancets and test strips
Blood glucose meters need two accessories in order to work: lancets and test strips.
A lancet is a device that pricks the skin to get a small blood sample. Lancets are available in many different brands and types. Some devices have preloaded lancets so you never have to touch them. Some allow you to get a sample with just one click, so it’s easy and fast. Others have settings for how deep the lancet goes based on what feels better to you.
Don’t share or reuse lancets — they’re only sterile the first time.
After you’ve drawn a drop of blood, you apply it to a test strip. These disposable strips absorb your blood and feed it into the blood glucose meter. You use a new one every time you take a sample.
Your test strips are made to work with your meter. You’ll need to buy the brand name or generic test strip that fits. They’ll come in a box with one or two vials of test strips.
Keeping Track of Data
Checking blood glucose is the best way to monitor your diabetes. However, it’s not just an important reading. Your health depends on how you use that data to take better care of yourself.
An important step is writing down or downloading readings so you can see how your daily activities affect your blood glucose. In addition to the reading, keep track of the date and time, as well as details like what you ate or how long you exercised.
Choosing a tracking method that works for you
The way in which you record your data is up to you. Paper logbooks, spreadsheets, and apps are all good options.
You may like to write readings down on a piece of paper or in a logbook. Recording the results with pen and paper can help you learn about your condition and interpret the readings.
Or you may like the convenience of having your readings stored in your meter. Meters can store hundreds of readings, although eventually you’ll need to download them onto a computer to free up more memory. Downloading them and viewing them in a software program or spreadsheet helps you see the big picture.
You can use a meter or CGM that automatically uploads results to the cloud over Wi-Fi or Bluetooth so you don’t have to physically plug your meter into a computer. You can then view these readings in a software program or app at your convenience.
There is no shortage of apps to help you track your blood glucose data. Search iTunes or Google Play for apps that might work for you. New ones are added all the time.
Make sure you bring your blood glucose readings with you when you visit your doctor or diabetes educator. Beforehand, ask your provider how she likes to look at readings in the office. Your provider may prefer a paper printout, or she may have a computer and software to download readings from your meter on site.
Putting the numbers to use
The most important part of gathering data is putting it to work. The best way to do this is to talk with your healthcare provider. Together, you’ll come up with goals and targets for your blood glucose. You’ll take your readings to your checkups and talk about why there were highs and lows — and what to do about them. As you get the hang of it, you may use the readings to learn when you need to add a snack to your meal plan or get more exercise during the day, for example.
How you use your readings also depends on how often you check your glucose level. If you check once a day, that reading might give you a general idea about how your medications are working. Think big picture. If you check three times a day, you might learn when you need to eat less (or different types of food), exercise more, or destress. Focus on making small changes.
Keeping a record is an individual action, but it’s important for everyone with diabetes. It’s universal. Whether you check your blood glucose once a day or seven times a day, you’ll see trends over time about how different things like food, exercise, oral medications, or insulin affect your blood glucose. The goal is to tweak those things to reach a balance so most of your readings are in your target ranges. You’ll find out more specifics about this in Part 4 on food and exercise.
Without data, you just have guesses. It doesn’t matter whether a reading is in range. The most important thing is to record it and discuss it with your healthcare provider.
It’s natural to feel disappointed if your reading isn’t what you expected. Try not to fall into this mind-set. It’s not helpful to view readings as “good” or “bad.” They’re just data giving you more information about your body and your diabetes.
Putting your data to work also means reducing the risk of complications like extremely high blood glucose (also called hyperglycemia), which can make you tired and thirsty or blur your vision, and extremely low blood glucose (or hypoglycemia), which can make you hungry, make you irritable, or even make you pass out. Very high blood glucose can eventually lead to or worsen diabetes complications, and both high and low blood glucose levels can be very dangerous if untreated. (Read more about high and low blood glucose in the next chapter.)