Managing diabetes: Blood glucose

Updated On Jan 12, 2022

Knowing how to manage your diabetes is vital. Here are a few guides that may be helpful in understanding your diabetes better.

Blood glucose 

Your body converts sugar (glucose) from the foods you eat into energy, releasing it from your body’s own tissues. After you eat, the levels of glucose increases. The pancreas responds by insulin moving the glucose from the bloodstream into the cells of the tissue. This therefore helps the blood glucose levels to a lower level. 

If someone has diabetes, blood sugars may increase due to the pancreas not making enough insulin or the insulin not working properly. As a result, the blood sugar level remains high. This is a condition called “hyperglycemia or diabetes mellitus”.

Check your blood sugar with a blood sugar meter (also known as a glucometer) or a continuous glucose monitor (CGM). The frequency at which you check your blood sugar depends on the type of diabetes you have and whether you take any diabetes medicines. Every individual’s recommended blood glucose level varies, so you should discuss this with your healthcare provider.

Typical times to check blood sugar:

  • Immediately after waking up, before you eat or drink anything
  • Before eating
  • After two hours of eating
  • When you feel giddy/confused/sweaty/very hungry
  • Before/after exercise
  • When you are sick or not eating well
  • At bedtime

The NICE target blood glucose levels:

The NICE target blood glucose levels for adults with type 1 diabetes, children with type 1 diabetes, and children with type 2 diabetes are listed below. Additionally, the International Diabetes Federation provides target ranges for people without diabetes.

Most healthy individuals have the following normal blood sugar levels:

  • When fasting, between 4.0 and 5.4 mmol/L (72 to 99 mg/dL) 
  • 2 hours after eating, up to 7.8 mmol/L (140 mg/dL)

Diabetes patients should aim for the following blood sugar levels:

  • Before meals : 4 to 7 mmol/L for people with type 1 or type 2 diabetes
  • After meals : under 9 mmol/L for people with type 1 diabetes and under 8.5mmol/L for people with type 2 diabetes

HbA1c tests do not directly measure blood sugar levels, however, the results of the test are influenced by how high or low your blood glucose levels have tended to be over a period of two to three months.

Diabetes or pre-diabetes can be diagnosed under the following conditions:

  • Normal: Below 42 mmol/mol (6.0%)
  • Prediabetes: 42 to 47 mmol/mol (6.0 to 6.4%)
  • Diabetes: 48 mmol/mol (6.5% or over)

Blood glucose testing 

Doctors use the following tests to find out if you have diabetes:

  • Fasting plasma glucose test – Blood sugar levels are checked after fasting for 8 hours
  • Oral glucose tolerance test – After fasting for 8 hours, a sugary drink is provided. Your blood sugar level will be checked 1 -2 hours and possibly 3 hours afterward. At 2 hours, a blood sugar level of 140mg/dL or lower is considered normal, 140-199mg/dL indicates you have pre-diabetes, and 200mg/dL or higher indicates you have diabetes
  • Random check – Clinicians test your blood sugar randomly, and considers the other symptoms of diabetes (e.g. peeing more, always thirsty, you’ve gained/lost a significant amount of weight)
  • HbA1c test – Measures your average blood sugar level over the past 2-3 months. 5.7% is normal, 5.7-6.4% indicates you have pre-diabetes, and 6.5% or higher indicates you have diabetes

Fasting blood glucose level 

  • To get an accurate plasma glucose level, you must have fasted for at least 8 hours prior to the test 
  • When you report to the clinic, a small sample of blood will be taken from a vein in your arm 

Blood glucose level

What it means

70-99mg/dL (3.9-5.5mmol/L)

Your glucose level is within the normal range

100-125mg/dL (5.6-6.9mmol/L)

You have an impaired fasting glucose level (pre-diabetes 

126mg/dL (7.0mmol/L) or higher on more than 1 testing occasion

You have diabetes