Blood glucose: what it means and how to test it at home

March 15, 2023
5 minute read

If you’re managing diabetes, or just keen to regularly check your own blood glucose levels, this step-by-step guide will give you the information and confidence to test, monitor and assess your blood glucose at home.

Blood glucose, also referred to as blood sugar, is the main source of energy in our blood used to fuel our body. It comes from our diet but is also produced by our liver, and stores can be released from our muscles.

How to test your blood glucose

If you're concerned about your blood glucose levels or if diabetes runs in your family, you can visit your GP who will measure your blood glucose levels by taking a small blood draw from your arm for testing. The test for diabetes is a measurement of your HbA1C level, which is the average blood glucose levels over the past three months. Based on the results from this test, your GP will be able to advise on the appropriate action(s) to be taken.

To test your blood glucose at home, you will need a blood glucose monitor, also known as a glucometer. This is a small hand-held device that tests your blood glucose by taking a small blood drop from a prick of your finger. Your GP can issue you with a glucometer or they can be purchased at a pharmacy. There are also alternative monitors that avoid pricking the finger which involve attaching a sensor to the back of your upper arm. You can find out more from the NHS.

When to test your blood glucose

It is recommended that you test your blood glucose levels several times per day to understand how your body reacts in between meals. For example, your blood glucose level will naturally rise after a meal. For people with diabetes, these changes will be greater and occur more often throughout the day.

The most recommended approach is a ‘fasted blood glucose test’ which is carried out first thing in the morning when you wake up as your blood glucose levels will not be influenced by food or drink. You can also test before meals, after meals and in the evening. Blood glucose levels vary from person to person and is heavily linked to your risk profile of developing diabetes, your diet and how active you are.  

Below is an example of a suggested daily testing schedule:   

  1. First thing in the morning (before any food/drink is consumed)
  2. Pre-lunch (3-4 hours after morning test)
  3. After lunch (1-2 hours after eating)
  4. Pre-dinner
  5. Post dinner (2-3 hours after eating)

How to use a finger prick monitor:

  1. Wash your hands with soap and water beforehand. Prepare the test strip and needle on the monitor.
  1. Choose which finger to test and give it a gentle squeeze a few times to allow the blood to flow to the base of your finger. Then place the device against your finger, avoiding the middle of your finger to too close to a nail. Press the plunger down with the other hand. You will feel a tiny prick on your finger.
  1. You may need to squeeze your finger some more to release some blood, then hold the monitor against your finger to place a small seed size amount of blood on the test strip.
  1. Before you look at the result, use a tissue to stop the bleeding on your finger. The monitor will take a few seconds to load on the screen your blood glucose level. Note your result and dispense of the test strip and needle according to your monitor.

For more information / guidance on using finger prick monitors, head to Diabetes UK.

Finger prick monitor in use

How to read the results of a blood glucose test

To gather a clear picture of your blood glucose levels, it is advised that you take detailed notes of each test result, date/time of test, and a list of all the food and drink consumed prior to the test.

Diabetes UK suggests the following mmol/L’s for type 1 and type 2 diabetes that represent a “healthy target.” The measure of blood glucose is in millimoles per litre (mmol/L), a scientific unit used to measure a substance.

For adults with Type 1 diabetes:

  • when you wake up and before meals: 5-7mmol/L
  • before meals at other times of the day: 4-7mmol/L
  • 90 minutes after meals: 5-9mmol/L

For adults with Type 2 diabetes: 

  • before meals: 4-7mmol/L
  • two hours after meals: less than 8.5mmol/L

Blood sugar monitor showing test reading

Useful resources

Diabetes UK - a source of information, research and support for Diabetes

NHS - latest guidance from the NHS

If you are experiencing any of the above symptoms or think you may suffer from either high or low blood glucose levels, we advise you to arrange an appointment with your GP as soon as possible. Alternatively, you can speak to one of our experienced Pharmacists for advice.

Content last reviewed on:
March 15, 2023
Next review date:
March 15, 2025
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