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Self-monitoring of blood glucose

Self-monitoring of blood glucose

Monitoring of blood glucose is an important and necessary part of managing diabetes. Monitoring allows you to find out whether your diabetes treatment plan is working, and it enables you to take control of your health. If you have type 2 diabetes, your healthcare provider will monitor your glycemic control using hemoglobin A1C testing on a regular schedule during office visits. The frequency of monitoring will be determined by how well your blood sugar is being controlled and other factors. Your provider may want to test you more frequently after a change in medication. If you use insulin therapy, your provider will have you do self-monitoring of blood glucose using a blood glucose meter.1,2

Self-monitoring of blood glucose using a blood glucose meter allows you to check your blood glucose level at any time and enables you to make changes in treatment to fine-tune your blood glucose level.3

How is self-monitoring of blood glucose performed?

Self-monitoring of blood glucose typically involves using a lancet which inserts into a spring loaded device to get a tiny drop of blood from your finger and applying the blood sample to a test strip which you insert into the blood glucose meter. The blood glucose meter then within seconds displays the result of the test. The frequency of daily testing will depend on the specifics of your treatment plan. For people with type 2 diabetes, the frequency of testing varies greatly depending on medication use and whether you take insulin or not.

Although specific steps for performing self-monitoring of blood glucose will vary depending the blood glucose meter you use (instructions will be available with your kit), there are some general guidelines that are common for most monitoring units. To ensure that you don’t transmit or acquire an infection (such as hepatitis B), remember that it is important never to share fingerstick lancing devices or monitoring equipment. The general steps for blood glucose meters are as follows:3:

General steps for home blood glucose monitoring

1. Wash and dry hands.
2. Insert lancet into lancet device.
3. Prepare glucose monitor with test strip.
4. Take a blood sample using lancet.
5. Apply blood to test strip in meter.
6. Dispose of lancet in sharps container.
  1. Thoroughly wash hands using soap and warm water, then dry hands.
  2. Insert a fresh lancet into the lancing device. If you use a lancet more than once, it can become dull and cause pain or injure your skin. So, always use a fresh lancet.
  3. Follow the manufacturer instructions for preparing your glucose meter and test strip.
  4. Obtain a drop of blood using the lancing device either from a fingertip or an alternate site, such as your forearm. Although an alternate site may involve less pain, blood taken from the fingertip will give you the most accurate results, best reflecting rapid rising or falling of blood glucose levels. If you find it difficult to obtain enough blood from your fingertip, try shaking your hand below the level of your waist, placing your fingers in warm water, or squeezing (sometimes called “milking”) your fingertip.
  5. After you lance your finger, apply the drop of blood to a test strip in the meter. The results should be displayed within several seconds.
  6.  After testing, properly dispose of your lancet in a puncture-resistant sharps container. Remember never to dispose of a lancet in your household trash.

How often should will I need to test my blood glucose?

The frequency of daily testing will depend on the specifics of your treatment plan. People with type 1 diabetes who depend on insulin injections typically need to test their blood glucose at least 4 times per day. For people with type 2 diabetes, the frequency of testing varies greatly depending on medication use and the need for insulin.3

Interpreting monitoring results

Self-monitoring of blood glucose is useful for determining whether your care plan, including diabetes treatments, are keeping your blood glucose on target. However, blood glucose results will change according to how active you are, what foods you have eaten, and what medications, such as oral and injectable diabetes medications and insulin, you are taking. So, to interpret your test results, you’ll need to take into consideration all of these factors. Your doctor will have you keep a record of your monitoring results, including details about medication dosage, food intake, exercise and activity, illness, and stress level. Keeping careful records will allow you and your doctor to review monitoring results during office visits and determine how well your care plan is working.3

Interpreting home glucose monitoring results

To accurately interpret your results, you will need to keep track of several factor that affect blood glucose levels.

Activity and exercise
Food and drink intake
Diabetes medication dosage and schedule

How accurate are home blood glucose monitors?

Blood glucose meters are generally accurate. However, different monitors may produce slightly different results and the accuracy can be affected by the test strip and the meter that reads your blood sample. It’s a good idea periodically to take your blood glucose meter along with you to an office visit and compare results using the monitor with laboratory results when you have blood work done. If you are suspicious about a reading because you feel like your blood glucose may be higher or lower, take a second reading from an alternate site. Just keep in mind that a fingertip blood sample is preferred because it more accurately reflects rapid increases or falls in blood glucose.

Keep in mind that the accuracy of your monitor is affected by factors other than the meter, including4:

  • How well the testing is performed, including how well you follow manufacturer instructions, such as washing and drying hands and storing test strips.
  • The number of red blood cells in your blood (this is called your hematocrit). If you are anemic or if you are dehydrated, your monitoring results may be less accurate.
  • – If you have taken a substance that interferes with the monitoring results (these include vitamin C or a drug like Tylenol). Instructions with your blood glucose meter will list substances that you should avoid around the time you are testing.
  • Temperature, altitude, and humidity can affect test results. The manufactures instructions for your unit will provide more information about testing conditions.
  • Test strips must be stored properly (according to manufacturer instructions), as direct light and humidity can affect the life of the test strip. Test strips that are stored in a cool place (above freezing) and away from the light and moisture have the longest life.

One idea for testing the accuracy of your blood glucose meter is to use a control solution, with a determined amount of glucose in liquid. Your monitor kit may come with a control solution for control testing purposes.5

Are there blood glucose monitors suited to me if I’m vision impaired?

There are blood glucose monitors made for people who have vision problems. These monitors have larger screens and there are even monitors equipped with sound that can speak to the user. If you have a vision impairment and want more information about blood glucose monitors, contact the National Federation of the Blind ( by telephone at 410- 659-9314 or by email:


Learn more about specific models of blood glucose monitors

Written by: Jonathan Simmons | Last reviewed: May 2014.
1. American Diabetes Association. Standards of Medical Care in Diabetes—2014. Diabetes Care 2014;37:S14-S80. -- 2. Inzucchi SE, Bergenstal RM, Buse JB, et al. Management of hyperglycemia in type 2 diabetes: a patient-centered approach: position statement of the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD). Diabetes Care 2012;35:1364-79. -- 3. McCulloch DK. Patient information: Self-blood glucose monitoring in diabetes mellitus (Beyond the Basics). Nathan DM, Mulder JE, eds. UptoDate. Wolters Kluwer Health. Accessed at: 2013. -- 4. Blood glucose monitoring devices. US Food and Drug Administration. Available at: Accessed on 021314. -- 5. Blood glucose meters: Consumer guide 2014. Diabetes Forecast. Available at: Accessed on 021314.