Blood glucose monitoring
One of the main aims of diabetes treatment is to keep blood glucose levels within a specified target range. The key is balancing your food with your activity, lifestyle and diabetes medicines. Blood glucose monitoring can help you understand the link between blood glucose, food, exercise and insulin.
Over time your readings will provide you and your health professionals with the information required to determine the best management strategy for your diabetes. Maintaining good blood glucose control is your best defence to reduce the chances of developing complications from diabetes.
Self-blood glucose monitoring allows you to check your blood glucose levels as often as you need to or as recommended by your doctor or Credentialled Diabetes Educator.
What do I need?
To test blood glucose levels, you need:
- A lancet device with lancets
Blood glucose meters are usually sold as kits giving you all the equipment you need to start. There are many different types, offering different features and at different prices to meet individual needs. Most of these are available from Diabetes Australia in your state or territory, pharmacies and some diabetes centres. Your doctor or Credentialled Diabetes Educator can help you choose the meter that’s best for you, and your Credentialled Diabetes Educator or pharmacist can show you how to use your meter to get accurate results.
How do I test my blood glucose levels?
To test your blood glucose levels, you prick your finger with the lancet and add a small drop of blood onto a testing strip. This strip is then inserted into the meter, which reads the strip and displays a number – your blood glucose level.
When and how often you should test your blood glucose levels varies depending on each individual, the type of diabetes and the tablets and/or insulin being used. Blood glucose levels are measured in millimoles per litre of blood (mmol/L). Your doctor or Credentialled Diabetes Educator will help you decide how many tests are needed and the levels to aim for.
Keeping a record of your blood glucose levels can be very helpful for you and your doctor or Credentialled Diabetes Educator. You can keep a diary or use a mobile phone app or website to record your levels.
When should I test my blood glucose level?
When you should test your blood glucose levels and how often you should test varies depending on each individual, the type of diabetes and the tablets and/or insulin being used. Your doctor or Credentialled Diabetes Educator will help you decide how many tests are needed and the levels to aim for. Possible times to test are:
- Before breakfast (fasting)
- When you are feeling unwell
Even though your meter may have a memory, it is important to keep a record of your readings in a diary and to take this with you to all appointments with your diabetes health team. This will provide both you and your diabetes health team with important information in deciding if and how your treatment may need to be adjusted.
Most meters on the market have software which allows you to download your records in different formats such as graphs and charts. Even if you can do this, it is still helpful to keep a diary, not only for your tests but also details of your daily activities, the food you eat and other relevant information. There are some apps that record all of this information in one place. Ask your doctor or diabetes educator how you can use a diary to help you to better manage your diabetes.
Testing four times a day is usually recommended for people with type 1 diabetes. However many people test more often, such as those using an insulin pump (CSII – continuous subcutaneous insulin infusion).
Why is it so important to test my blood?
Regular testing and recording of your blood glucose level can reinforce your healthy lifestyle choices as well as inform you of your response to other choices and influences.
Importantly, blood glucose level pattern changes can alert you and your health care team to a possible need for a change in how your diabetes is being managed.
Testing your blood glucose levels will help you to:
- Develop confidence in looking after your diabetes.
- Better understand the relationship between your blood glucose levels and the exercise you do, the food you eat and other lifestyle influences such as travel, stress and illness.
- Know how your lifestyle choices and medication, if used, are making a difference.
- Find out immediately if your blood glucose levels are too high (hyperglycaemia) or too low (hypoglycaemia), helping you to make important decisions such as eating before exercise, treating a ‘hypo’ or seeking medical advice if sick.
- Know when to seek the advice of your diabetes health team about adjusting your insulin, tablets, meal or snack planning when blood glucose goals are not being met.
Times to test more often
There will be times when you need to test more often, however you should first discuss this with your doctor or Credentialled Diabetes Educator. Example of these times include when you are:
- Being more physically active or less physically active
- Experiencing changes in routine or eating habits, e.g. travelling
- Changing or adjusting your insulin or medication
- Experiencing symptoms of hypoglycaemia
- Experiencing symptoms of hyperglycaemia
- Experiencing night sweats or morning headaches
- A female planning pregnancy or are pregnant.
- Pre/post minor surgical day procedures
- Your Credentialled Diabetes Educator can help you work out a testing plan especially for you.
Effective management of diabetes is all about aiming for a careful balance between the foods you eat, how active you are and the medication you take for your diabetes. Because this is a delicate balance, it can be quite difficult to achieve ideal control all the time.
The ranges will vary depending on the individual and an individual’s circumstances. While it is important to keep your blood glucose levels as close to the target range of target range between 4 to 6 mmol/L (fasting) as possible to prevent complications, it is equally important to check with your doctor or Credentialled Diabetes Educator for the range of blood glucose levels that are right and safe for you. Therefore the following information should be treated only as a general guide.
Glucose level targets
Blood glucose levels are measured in millimoles per litre of blood (mmol/L). Target ranges may differ depending on your age, duration of diabetes, the type of medication you are taking and if you have any other medical problems. Speak with your doctor about your individual target ranges.
Normal blood glucose levels are between 4.0–7.8mmol/L.
1 Targets are as recommended by the American Diabetes Association. NHMRC guidelines are currently under development.
2 Targets are as recommended by the NHMRC, Blood Glucose Control in Type 2 Diabetes, (2009).
Inconsistent highs & lows
Sometimes you may get a lower or higher blood glucose reading than usual and you may not be able to figure out the reason. When you are sick with a virus or flu, your blood glucose levels will nearly always go up and you may need to contact your doctor. There are a number of other common causes for blood glucose levels to increase or decrease. These include:
- Food – time eaten, type and amount of carbohydrate for example: bread, pasta, cereals, vegetables, fruit and milk
- Exercise or physical activity
Contact your doctor or Credentialled Diabetes Educator if you notice that your blood glucose patters change or are consistently higher or lower than usual.
Getting accurate results
There are many reasons why your test results could be inaccurate. The best defence against this is to see a Credentialled Diabetes Educator to learn how to use your meter, prepare your lancing site and how to maintain your meter and equipment.
What if the test result doesn't sound right?
If you’re not convinced that a result is correct, here’s a suggested check list:
- 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 the test? (handling sweet foods such as jam or fruit can give higher results)
- Is the meter too hot or too cold?
- Is the calibration code correct?
- 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 can 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.
What is a glycosylated haemoglobin (HbA1c) test?
The HbA1c test shows an average of your blood glucose level over the past 10–12 weeks and should be arranged by your doctor every 3–6 months.
Does the HbA1c replace testing my own BGLs?
No, the HbA1c test doesn’t show the highs and lows that your home testing shows. Therefore it does not replace the tests you do yourself but is an added tool in giving the overall picture of your blood glucose management.
What HbA1c do I aim for?
The goal for most people with diabetes will be in the 6.5-7 percent (48-53mmol/mol) range however this may need to be higher for some people including children and the elderly. Your doctor or Credentialled Diabetes Educator can help you decide on a target that is both appropriate and realistic for your individual circumstances.
Many hospitals have a diabetes clinic where you can find out more about blood glucose monitoring. Contact your local hospital for your nearest diabetes clinic or call us on 1300 136 588.