But What Do the Numbers Mean?

When you test your blood glucose level, your meter will provide you with a number. This number will vary, but do you know what the numbers mean?

These numbers tell you how much sugar (in milligrams or mg) is in a deciliter (1/10th of a liter or dL) of blood at that moment. The numbers change based on what, when and how much you ate or exercised, the type, time and dose of insulin or diabetes pills you took and your stress level.

But what do the numbers mean to you? The first thing to decide is where you would like to keep your blood sugar. It's not possible to keep your blood sugar normal all of the time. It makes more sense to choose a range, for example 120-180 before meals. Choose your range based on how hard you are willing and able to work and the advice given by your health care team. Choose a range you can reach, where you feel well and that will help lower your risk for the complications of diabetes.

Think of your range as a target. You may not always hit your target, but it is where you are most of the time that matters.

Once you choose your target range, here are some tips for understanding your numbers.

• If you see a number that is higher or lower than you expect, think about why. Did you eat less than usual? Did you eat at a different time? Did you get more exercise than usual? Did you take your diabetes pills or insulin at a different time than usual? Are you more stressed?
• Looking at each blood sugar reading can be confusing. If you write down your blood sugar readings in a logbook you can look for patterns. Look at all of your readings at the same time of day for a week or two. Is your blood sugar usually in your target range, or too high or low most days at that time? On days when it was different from usual, can you think of a reason? If your blood sugar level is often out of your target range -- your medicine, meal plan, activity or schedule may need adjusting.
• Your fasting blood sugar sets the stage for the rest of the day. If your before breakfast blood sugar reading is high, its harder to bring it into range once you eat. Your before breakfast blood sugar is affected by your evening snack, your dose of bedtime insulin or diabetes pills, the sugar that your liver makes during the night, and hormones that cause your blood sugar to go up during the night. To lower your fasting blood sugar you can change your evening medicines (the type, dose or time you take them) or adjust your snack.

It can be frustrating to try to understand what is happening with your blood sugar and keep it in the target range. Because so many things can affect your blood sugar, it is hard to always figure out what the numbers mean. Remember that your reading is simply a measure of the sugar in your blood. It is not a judgement of the kind of person that you are or whether you are good or bad. Blood sugar tests give you the information that you need to make choices and decisions about how you care for yourself and your diabetes. You are not doing it for your doctor, your spouse, children, educator or dietitian. It's not worth all of the pain, cost and hassle unless you are doing it for yourself to make decisions today and for your future health.

Here is a checklist to help you understand what the numbers mean. Ask yourself:

• Is it in my target range?
• Is it often outside the target range at this time of day?
• What might have caused it?
• Can I do something differently next time?

Written by Martha Funnell, MS, Rn, CDE

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