Home Blood Glucose Monitoring for People with Diabetes

Checking your blood sugar at home, sometimes called self blood glucose monitoring (SBGM), is an important step in diabetes management. Because individualized diabetes care is associated with better diabetes management, it is important to get your doctor's advice on how often you should test your blood sugar. This includes recommendations for what time of the day you should test your blood sugar, and your personal target ranges for blood sugar control. This article is intended to provide general guidelines for SBGM in order to enhance discussion with your doctor. It is not a substitute for your physician's guidance.

When testing your blood sugar at home, it is important to talk to your doctor or certified diabetes educator about each of the following, which we'll discuss in detail below:
  1. Choosing the best glucose meter for you
  2. Using good technique when testing your blood sugar
  3. When should you test your blood sugar?
  4. How to use and interpret the numbers on the screen
  5. Proper disposal of used testing supplies

How do I choose the best glucometer?

Today, there are many quality-made home blood glucose meters on the market. Choosing the right one for you can be a little overwhelming, so here are some factors to consider.

Many health insurance plans offer some type of coverage for diabetes testing supplies. However, in many cases, your insurance company may recommend a "preferred meter" or a "preferred brand" that must be used in order to avoid paying a high co-pay. It is best to call your insurance company and ask if there is a preferred brand of glucometer. It may be financially wise for you to use the preferred meter to limit your ongoing costs.

Diabetes supplies can be expensive. Test strips for most branded meters cost roughly $1 per strip—this can add up to $30 to more than $100 per month depending on how often you test. If you do not have health insurance and must therefore pay out-of-pocket for your testing supplies, using an off-brand or private label meter may help ease the financial strain. These are fairly easy to find in most pharmacies and test strips typically cost about half the price of the brand-name strips, so shop around.

If you have physical limitations, there are many glucometers on the market today that are well suited for people with arthritis or conditions that limit the use of their fingers and hands. Many meters also have features that are useful for people who are visually impaired. Choose the meter that is easiest for you to use if you have a particular need.

What is the proper technique for testing my blood sugar?

Poor technique is one of the most common causes of inaccurate blood sugar readings. Correct operation of each glucometer varies from brand to brand—and even meter to meter within the same brand. Be sure to read the instructions for use carefully. If you need help with the proper use of your meter, contact your certified diabetes educator or call the manufacturer (typically a toll-free number is provided on the back of the meter).

While each meter may operate differently, here are a few "best practice" tips everyone can use to help ensure accuracy of results:
  • Gather all of the supplies you need to test your blood sugar. Your meter, your test strips, and your lancing device loaded with a lancet should be in one place and ready to go. You may also want a clean tissue or a bandage to cover your skin after you test.
  • Wash your hands. It is important to wash your hands to kill germs and prevent infection every time you test your blood sugar, but cleansing your hands also frees them of any food residue that might contain sugar. If you have sugar on your skin, it can affect your test result, leading to an inaccurate reading. While it is widely thought that you need to swab your finger or alternate site area with alcohol, soap and warm water are fine. In fact, soap and water are generally preferred because they are not as drying to the skin. If you choose to use alcohol swabs to cleanse, make sure it has dried completely before you test. Alcohol in the blood sample can cause the reading to be inaccurate as well.
  • Store your supplies properly. Your glucometer and test strips can be damaged very easily. Proper storage can minimize the chances that your supplies become damaged and therefore unreliable. Keep your meter and strips out of direct sunlight and away from moisture, or areas of high humidity like the bathroom. They can also become damaged it they get too hot or too cold.
  • Use control solution as recommended. This can help determine if your test strips are in working order and giving accurate results. Follow the test strip manufacturer's guidelines or talk to your diabetes educator for more specific information about this useful tool.

When should I test my blood sugar?

It is recommended that you talk to your doctor or certified diabetes educator about specific blood glucose testing times. Together, you can decide on a plan that will help you achieve your blood glucose management goals. In general, blood glucose testing can be done at any of the following times:
  • Fasting (testing first thing in the morning before you've had anything to eat or drink)
  • Before any other meal (lunch and/or dinner)
  • 2 hours after any meal (breakfast, lunch, and/or dinner)
  • Before going to bed
  • Anytime you feel "funny" (high and/or low blood sugar can affect how you feel)

What should I do with the results of my blood sugar tests?

As a certified diabetes educator, I hear this question a lot. Unfortunately, there is no short answer. SBGM can be used for a number of decisions regarding your diabetes care. Here are three things you can do with your glucometer results to help with your diabetes management.
  1. Record the number. Hopefully, this is all you'll need to do with the results of most of your home tests. Those numbers are a valuable tool for your doctor to use when making decisions about your diabetes care plan. Record the result of every test every day, and take your log book with you to EVERY doctor's appointment. 
  2. Compare the results to your target ranges. Testing your blood sugar at home allows you and your diabetes care team to see how well you are controlling your diabetes. The following blood glucose ranges are associated with lower risk of developing long-term diabetes-related complications.
    According to You should aim for this range
    American Diabetes Association 80-130 mg/dL before meals

    less than180 mg/dL 1-2 hours after the beginning of a meal
    American College of Endocrinology 80-120 mg/dL before meals

    80-140 mg/dL 2 hours after a meal

    Please note that you should develop individualized goals for your blood sugar with your doctor and diabetes care team.
  3. Identify when there is a problem. Testing blood glucose at home helps identify when you may need your doctor's help. Your health care provider can provide specific guidelines to you about when to seek medical help, but in general, you should contact your physician if:
    • Your blood sugar runs over 180 mg/dL for 2 to 3 days and you can't explain why.
    • You have type 2 diabetes and you get a blood sugar reading over 300 mg/dL on one occasion
    • You have type 1 diabetes and you have a blood sugar reading over 250 mg/dL and you have ketones in your urine on one occasion
    • You have several episodes of hypoglycemia (blood sugar below 70 mg/dL)
    • You ever have any questions or concerns about your blood sugar readings

What should I do with my used diabetes testing supplies?

Lancets (small, needle-like items) that have been used to do a finger or alternate site stick for home blood sugar testing are considered household medical waste. They need to be disposed of carefully so that they do not injure another member of the household (including pets) or a sanitation worker. Talk to your doctor, certified diabetes educator, or call your public health department to learn about specific guidelines or laws about household medical waste disposal in your city or state.

The main thing to remember is to NEVER throw used lancets directly into the trash—even if the small plastic cap has been replaced. Typically lancets should be disposed of one of two ways:
  1. A Sharps container. Most likely, you've seen these in your doctor's office. They are usually red and made of hard plastic. They are available for purchase in most pharmacies, and can occasionally be found free of charge at various community agencies. Typically, there is a fee for mail-away removal or at a drop-off location.
  2. A hard, airtight container. If you don't have a sharps container, it is easy to make your own. Good options are empty detergent bottles, empty soda bottles, and empty milk jugs. When full, make sure the cap is secure and clearly mark the container with the word "sharps" in large letters.
For more specific information or help, talk to your health care provider. The American Diabetes Association's National Call Center also offers live advice from 8:30 a.m. to 8 p.m. EST, Monday through Friday at 1-800-DIABETES or 1-800-342-2383.

This article has been reviewed and approved by Becky Hand, Licensed and Registered Dietitian.