Self-Monitoring of Blood Glucose (SMBG) is an approach whereby people with diabetes measure their blood sugar (glycemia) themselves using a glycemic reader (glucose meter). Based on the reading, they can adjust or check the effect of their treatment (diet, exercise, insulin, antidiabetics, stress management). Within the wider context of diabetes self-management, self-monitoring supports the maintenance of blood glucose (sugar) at levels as close as possible to target values.

Are there problems with self-monitoring?

A person with diabetes may find self-monitoring problematic for several reasons: the need to carry materials and prick themselves several times per day, frustration with unexpected results. Nevertheless, when a person self-monitors according to the recommendations, and understands the benefits of this approach, self-monitoring becomes an important resource.

Self-monitoring lets you:

Check the impact of different treatment elements on your blood glucose and make adjustments, if necessary.
Complete the information provided by glycated hemoglobin (A1C).
Identify, quickly treat and prevent hypoglycemia or hyperglycemia.
Develop confidence, autonomy and feel safe.

Importance of training

To fully benefit from self-monitoring, it is essential that you be trained by a health professional. Your training should include the following elements:

The technical aspects of self-monitoring;
Blood glucose targets;
When and how often to measure blood glucose;
What action to take based on the readings obtained;
Re-evaluating (every 3 to 6 months) when, and how often, to self-monitor, based on your clinical condition and readings.

Without this information, self-monitoring of your blood glucose will not fulfill its potential. This could affect your motivation, and the attainment of your goals.

How do I measure my blood glucose?

The first step is to meet with a health professional. After identifying your characteristics and needs, she will recommend a glucose meter, which you can buy at a drugstore, along with all the other materials necessary for self-monitoring: lancets (needles), a lancing device (to take blood), test strips and tissues.

You will then learn how to measure your blood glucose properly:

Wash your hands with soapy water and dry them well.
Insert the test strip into the glucose meter.
Insert the lancet into the lancing device.
Prick the end of a finger (on the side).
Gently squeeze the end of your finger, if necessary.
Apply the blood to the test strip.
Wait a few seconds (the time varies by type of meter).
Read and write down the result in a logbook or store it in the glucose meter.

Self-monitoring times and frequency

When and how often to self-monitor is determined by the type of diabetes, the prescribed treatment, the risk of hypoglycemia, and your ability to understand the concepts taught. Thus, self-monitoring varies from person to person.

Situation	Recommended self-monitoring times and frequency
Person being treated with four or more insulin injections per day, or with an insulin pump	At least 4 blood glucose readings per day (before meals, at bedtime and, in certain circumstances, 2 hours after a meal and when any other situation presents a risk of hypoglycemia)
Person with type 2 diabetes being treated with a single insulin injection per day and antidiabetic medication	At least 1 blood glucose reading per day at different times of the day (fasting, before meals, 2 hours after a meal or at bedtime)
Person with type 2 diabetes being treated with insulin secretagogues*	At the first sign of hypoglycemia
Person with type 2 diabetes being treated with antidiabetic medication with no hypoglycemia or lifestyle risks	Generally not required, except in specific situations

* gliclazide (Diamicron^® and Diamicron^® MR), glimepiride (Amaryl^®), glyburide (Diabeta^®), repaglinide (GlucoNorm^®).

Certain situations may require a person with diabetes to measure blood glucose more often. In the following situations, discuss your self-monitoring with your health-care team:

A recent diabetes diagnosis;
Starting a new treatment;
Not reaching target blood glucose levels;
Planning a pregnancy, or becoming pregnant;
A job requiring increased blood glucose monitoring;
A medical condition that could affect blood glucose control.

How to I make sure the results are accurate?

You can verify that your glucose reader and test strips are working together properly using the control solution that usually comes with the meter. If not, you can buy the control solution at most drugstores, or directly from the manufacturer. We recommend that you check the accuracy of your meter’s readings at least once a year by comparing a fasting reading with a reading done at the same time in a laboratory. Consult a health professional about the acceptable variance between the two readings. Also, always follow your meter’s user instructions.

To avoid false readings, your test strips and glucose meter must be in good condition. Make sure that:
The expiry date printed on the test-strip container has not been reached or exceeded
The test-strip container was not left open after you took out a test strip
The test strips are in their original container
The test strips have been kept away from moisture, and stored at a temperature between 4 and 30 degrees Celsius
The test strips have not been contaminated by dust or other substances
There is no dust or dried blood on the opening of the test strip
The glucose meter has not been left in direct sunlight
The glucose meter has not been exposed to moisture, or to temperatures below 5 degrees Celsius or higher than 30 degrees Celsius
The glucose meter has not been dropped, or been in contact with a liquid

Preventing infection

In addition to hand washing, it is important to use a new lancet for each test. Discard the lancet and used test strip in a biohazard waste container available at most drugstores.

Conclusion

Blood glucose self-monitoring is a self-control tool for diabetes. However, taking readings more often and at other times than those recommended, or without training, may not provide any clinical benefits. For some people, self-monitoring can even be stressful. Training is essential because it is important to know how often you need to measure your blood glucose, how to interpret the readings, what action you need to take in response, and how independent you feel regarding your diabetes. Do not hesitate to discuss any of these issues with your health-care team.

Self-monitoring of blood glucose