Testing your blood glucose?

Testing your blood glucose, also known as Self-Monitoring of Blood Glucose (SMBG), is a method of checking how much glucose (sugar) is in the blood using a glucose meter -- anywhere, anytime.

Here, you’ll learn some basics about:

  • Blood sugar targets for adults
  • How your doctor tests your blood
  • The importance of self-testing
  • When to test and what to look for
  • How to share results with your doctor

Blood glucose targets for non-pregnant adults2

Before meal: 4.4 -7.2 mmol/L
After meal: less than 10.0 mmol/L

How your doctor tests your blood -- the A1C test

Your doctor uses what is called an A1C (Glycosylated Hemoglobin) test to see what your average blood glucose level has been over the last two to three months.
Used for both Type 1 and Type 2 diabetes, it gives you and your doctor an indication on how well you are responding to your treatment regimen, and if any adjustments are necessary. The goal is to keep your level below seven percent (7%).2 The A1C test is sometimes referred to as the hemoglobin A1c, HbA1c or glycohemoglobin test.

The connection between A1C and average blood sugar levels.3

A1C and average blood sugar levels

The importance of self-testing

Your A1C test result will not show the daily effects of food choices and your activity. A blood glucose meter is the best way to observe and track the immediate effects of food choices and activity on your blood glucose levels. This allows you to take immediate action to bring your glucose levels within range if needed. Your doctor will also rely upon your blood glucose meter results to assess and adjust your treatment regimen.

When to test and what to look for – a practical guide

Use this simple chart to remind you when to test and what to observe to help you manage your blood glucose level on a daily basis.

When to test What to look for
First thing in the morning, before you eat How did your body/medication regulate your blood glucose overnight?
Before every meal How is your choice of food and portion affecting your blood glucose?
How is your medication working to manage your blood glucose when you eat?
How should you adjust your food choices and portions going forward?
Two hours after meals Has your blood glucose returned to target after a meal?
Before physical activity Do you need a snack before engaging in an activity?
During and after physical activity How does physical activity affect your blood glucose?
Does your activity have any delayed effect on your blood glucose?
When you feel sick or stressed Is your illness or stress level affecting your blood glucose level?
Before going to bed Do you need a snack before bed?
As suggested by your healthcare professional How well is your medication working?
Before driving Is your blood sugar within a safe target to drive?

When to test your blood glucose more often:

  • When you feel any signs of hypoglycemia (low blood sugar) or hyperglycemia (high blood sugar); the signs and symptoms are indicated below
  • When you have new medicine prescribed
  • When your medication dosage is adjusted
  • If you include a new variety of food in your meals

Low blood sugar – hypoglycemia
Hypoglycemia means "low blood glucose. It is sometimes called a "hypo" and it can happen at any time during the day or night. You suffer from hypoglycemia when your body has insufficient sugar to use as energy, or when your blood glucose level is 70 mg/dL (3.9 mmol/L) and below.
Signs and symptoms of low blood sugar include:

  • Sudden, extreme hunger
  • Headache
  • Blurred vision
  • Trembling
  • Weakness/tiredness
  • Cold sweat
  • Fast heartbeat
  • Anxiety/nervousness
  • Irritability

What to do if you have low blood sugar:

  • Check your blood sugar to confirm that your blood glucose is at a level of 70 mg/dL and below.
  • Apply the 15/15 rule:
    -Have 15 grams of a quick-acting carbohydrate, for example: a glass of fruit juice; three to four teaspoons (1 tablespoon) of sugar in water; or five-six hard candies.
    -- Or-- you can take glucose gel or glucose tablets (see label for 15g amount)
    - Wait 15 minutes and check your blood sugar again.
    - If your blood glucose level is still low, continue to:
    -- Alternate 15 grams of glucose with waiting 15 minutes to test your blood glucose until it reaches an acceptable target.
  • Be sure to eat your next meal to prevent another low blood sugar reaction.
  • If symptoms persist, call your doctor.

High blood glucose: hyperglycemia
High blood glucose can occur when your food, activity and medication are not balanced: too much food, not enough activity and not enough medicine. It can also happen when you are unwell or under stress. If you have high blood glucose levels, you may be more prone to infection. And an infection can cause your blood glucose level to rise even more.

Signs of hyperglycemia
Hyperglycemia or high blood glucose is a key indicator of diabetes and therefore, the symptoms are the same as the symptoms of diabetes. These include:

  • Frequent urination
  • Excessive thirst and/or hunger
  • Dry mouth
  • Unexplained weight loss
  • Blurred vision
  • Lack of energy and extreme tiredness

What to do if you have high blood sugar:

  • Call the doctor to see if a change in medication is needed.
  • Check your blood glucose regularly.
  • Drink more water to help remove excess sugar from your blood through urine.
  • Do moderate exercise if your blood glucose is less than 16.7 mmol/L.
  • Refrain from exercise if blood your blood glucose is over 16.7 mmol/L and ketones are found in your urine.
  • Reduce food portions in succeeding meals.

Recording your blood glucose results:

  • Keep a log book handy, where you can manually record your blood glucose readings.
  • You can find log books at your doctor’s office, health care centers, and even online.
  • Always update your log book and take it with you to your doctor visits so that he and your health care team will have a clearer understanding of your blood glucose profile, which will help them in prescribing the proper treatment plan.





2. American Diabetes Association. (ADA) Glycemic Targets Sec. - In Standards of Medical Care in Diabetes - 2016. Diabetes Care 2016; 39 (Suppl. 1): S43.
3. A1c/eAG – ADA Diabetes Advisor series www.diabetes.org – accessed April 4, 2016.




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