Monitoring
Blood glucose monitoring is the process of checking the concentration of glucose levels in the blood stream and/or in the fluid between the cells.
This process is important for assisting people living with diabetes know how their blood glucose levels change.
It helps individuals make informed decisions about strategies for diabetes management by.
- Allowing them to understand the impact of food, physical activity, medications, stress and illness on their blood glucose levels,
- Providing knowledge on when to consult with their healthcare professionals and
- Improving confidence in diabetes self-management.
How to monitor
Blood glucose monitoring can be done by use of blood glucose meters, continuous glucose monitors (CGMs) and HbA1c check.
When using a blood glucose meter, blood is obtained from a small prick to the finger using a finger pricking device with needles (lancets). Using a strip inserted into the meter, the drop of blood is sucked from the finger onto the strip and after a few seconds the reading of the blood glucose level is displayed onto the meter screen.
Check with your credentialled diabetes educator or local pharmacist on how to access a free blood glucose meter and subsidised blood glucose strips under the NDSS. It is important that education on how to use the blood glucose meter is provided for obtaining accurate results. There is also a variety of  blood glucose meters available from the Diabetes SA shop at a discounted price for members. This form of monitoring displays what your glucose level is at that instant.
Continuous blood glucose monitors are sensor devices that can be placed onto the skin to provide continuous readings of the glucose levels within the subcutaneous tissue of the body 24/7. Since the sensor readings are for glucose levels within the subcutaneous tissue, it is important to note that there can a lag of 5 – 10 minutes in the result compared to those obtained from blood glucose meter.  CGMs may need to be replaced between 10 – 14 days depending on the type and their results can be sent to a compatible receiver, smart phone app or insulin pump. The NDSS provides access to free or subsidised CGM for registered members living with type 1 diabetes.
Blood glucose monitoring can also be done via the HbA1c pathology blood test. This provides the mean glucose level over the last two to three months period. This reflects the amount of glucose that attaches onto the red blood cells. The average life span of red blood cells is two to three months, therefore the HbA1c test provides the mean glucose levels for that period. The doctor generally requests for the HbA1c test to be done every 3 to 6 months depending on your personal circumstances and health.
When to monitor
The frequency for blood glucose monitoring depends on the current treatment that one is on for managing diabetes. It is important that your check with your diabetes healthcare professional on the appropriate times for you to monitor your glucose levels.
The most common times are;
- First thing when you wake up (fasting)
- Before meal (if on insulin)
- Two hours from the start of a meal
- When experiencing hypoglycaemeic symptoms
- When feeling sick/unwell
- Before, during and after physical activity/exercise
- When concerned about your diabetes or unsure about sensor readings
- Check that your bgl is above 5mmol/l before driving and check every 2 hours during long trips.
Developing a structured self- monitoring profile with your health care professional can provide informed data on the most appropriate pattern suitable for monitoring your blood glucose levels. This guide can be used as an example. It is recommended to contact your diabetes health care team, if your blood glucose trends change or are repeatedly out of the set target range.
General recommended targets
Type 1
Fasting
4.0 – 7.0 mmol/l
Two-hour postprandial
5.0 – 10. 0 mmol/l
Type 2
Fasting
4.0 – 7.0 mmol/l
Two-hour postprandial
5.0 – 10. 0 mmol/l
Gestational
Fasting
=< 5.0 mmol/l
Two-hour postprandial
One – hour postprandial =< 7.4mmol/l
Two-hour postprandial =< 6.7 mmol/l
*Targets are general in nature, speak with your healthcare team for targets specific to you.
RACGP
It is normal to have blood glucose levels changing throughout the day. However, it is not normal to have very low or high glucose levels.
If glucose levels drop below 4 mmol/l and not treated this can turn into a life-threatening situation.
If glucose levels register high or you are feeling sick, there is an increased risk of developing short -term complications such as dehydration, or Diabetes ketoacidosis, hence important to check for ketones in urine or blood and follow your sick day management plan. The risk of developing long-term complications like stroke, heart disease, kidney disease, nerve and vison problem is also increased when glucose level remain high over time.
What to do when results are suspected to be incorrect.
It is important to have your blood glucose meter checked for accuracy, especially when you suspect the readings to be incorrect. This can be done using a control solution. Organise this check with either your credentialled diabetes educator or pharmacist.
Also check that your strips are not expired, inserted correctly into the meter and have not been exposed to extreme cold or hot temperatures.
It is recommended that the blood glucose meter is clean, has a well charged battery and hasn’t been exposed to extreme cold or hot temperatures.
It is important to let your doctor know what other medications you are currently consuming including supplements, as some substances have been known to have an interference on the accuracy of blood glucose meter readings as well as that for CGMs.
