Blood glucose monitoring can help you to keep your blood glucose level in your recommended target range. 

To live well with diabetes, it’s important that you keep your blood glucose levels as close to target range as possible. Monitoring, recording and understanding your blood glucose levels (BGLs), often referred to as blood sugar levels, is important for both you and your health care team. 

Why is it important to monitor your BGLs? 

• Performing finger prick checks gives you an immediate BGL. This can guide you to know when to seek medical assistance and/or advice from your health care team. 
• Recording your BGLs to share with your health care team provides important information about your diabetes self-management. 
• To know whether your diabetes management plan is right for you. 
• To understand the relationship between your BGLs and medications, food, physical activity and other lifestyle factors such as travel, stress and illness. 
• It tells you how you are going with your diabetes self-management which can help increase your confidence. 

When should I check my BGLs? 

The number of times a day you check your BGLs will depend on what type of treatment you are taking e.g. insulin. Your diabetes team can advise when and how often to monitor. In general, you can check: 

• When you wake up – this measures your ‘fasting’ glucose level 
• Before a meal (if you take insulin) 
• 2 hours after a meal (to see the effect of the meal or mealtime insulin dose) 
• Overnight: 2 -3am (do this occasionally if you are on a basal insulin) 

Also do BGL checks: 

• Before driving any vehicle – you need to be above 5.0mmol/L to drive 
• When you experience a hypo 
• Before and after any physical activity (eg, walking, gardening, exercise) 
• If you become unwell 
• Whenever you are concerned about your diabetes.  

Structured self-monitoring involves checking your blood glucose levels at certain times of the day (for instance after meals) for a given period (i.e. two weeks) and then working with your diabetes healthcare team to figure out how food, physical activity and medications are impacting your blood glucose levels. 

How do I monitor my BGLs? 

Glucose levels can be monitored using a blood glucose meter, Flash Glucose Monitor (Flash GM) or Continuous Glucose Monitor (CGM).  

Blood glucose meters 

A blood glucose meter uses a small drop of blood to provide you with an immediate BGL. You will also need a finger pricking device with lancets (needles) and blood glucose monitoring strips. 

There are a wide variety of blood glucose meters available, however, not all blood glucose monitoring strips are subsidised by the Pharmac. Ask your diabetes educator or community pharmacist to help you choose a meter that suits your needs and show you how to use it. For accurate results the correct technique is also needed. 

Flash Glucose Monitors (Flash GM) 

A Flash GM is a sensor worn on the arm for 2 weeks. The sensor reads the level of glucose in between the cells just underneath the skin. The sensor needs to be scanned with a reader or smart phone application (app) to display the result. The sensor reads glucose levels every 5 minutes and retains 8 hours of readings which can be downloaded to give you and your diabetes team more insight into your blood glucose management. Flash GM can now be set to alarm when glucose levels are outside your target range. It is important to know that Flash GMs do not measure blood glucose levels so you will still need to do finger prick checks in certain circumstances. This is because Flash GM readings lag behind blood glucose readings by 5-10 minutes. 

Continuous Glucose Monitors (CGM) 

A CGM is a device which reads the level of glucose in between the cells just underneath the skin continuously. The device consists of a sensor and a transmitter. The sensor is replaced every 1-2 weeks and reattached to the reusable transmitter device. The continuous glucose reading can be sent to a receiver, smart phone app or insulin pump. CGMs can be set to produce audible alarms when glucose levels are outside of the healthy range, for example overnight. It is important to know that CGMs may  require calibration with twice daily blood glucose meter readings because CGM readings lag behind blood glucose readings by 5-10 minutes. 

What if the blood glucose check result doesn’t sound right? 

If you’re not convinced that a result is correct, here’s a suggested check list: 

• Have the strips expired? 
• Is the strip the right one for the meter? 
• Is there enough blood on the strip? 
• Has the strip been put into the meter the right way? 
• Have the strips been affected by climate, heat or light? 
• Did you wash and thoroughly dry your hands before doing a check? (handling sweet foods such as jam or fruit can give higher results) 
• Is the meter clean? 
• Is the meter too hot or too cold? 
• Is the battery low or flat? 

All meters will give a different result with a different drop of blood. As long as there is not a big difference (more than 2mmol/L) there is not usually cause for concern. 

The accuracy of all meters can be checked with meter-specific liquid drops called control solutions. If you are concerned, you can arrange to have your meter checked with a control solution. Your Credentialled Diabetes Educator or pharmacist may be able to help you with this. 

Caring for strips 

It is important to care for your strips so that you get an accurate reading. To do this, refer to the manufacturer’s instructions. It will include recommendations like: 

• Storing them in a dry place 
• Replacing the cap immediately after use 
• Checking the expiry date is valid. 

How can I record my BGLs? 

Keeping a record of your blood glucose readings is only helpful if you are going to use your results to manage your diabetes. Share your readings with your diabetes health care team and ask them how to interpret your readings to make decisions about your diabetes management. 

• A paper diary. Write your BGLs down. Some blood glucose meter manufactures make a diary or your health care team may also have one for you to use. 
• Phone apps. Some meters can Bluetooth your BGLs directly to your smart phone via an app. The app stores this information for you and can also be sent directly to your health care team. 
• Your blood glucose meter. Some health care providers are able to download the information from your meter. You would need to give your meter to your team for downloading. 

Blood Glucose monitoring retrieved from Blood glucose monitoring | Diabetes Australia https://www.diabetesaustralia.com.au/managing-diabetes/blood-glucose-monitoring/