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How to test your blood sugar

Blood sugar fluctuates over time due to various factors. Monitoring your blood sugar levels can help you keep track of how your body reacts to food, exercise and medication and how well you are controlling your diabetes.

When should you monitor your blood sugar level?

You may require regular blood sugar monitoring. Your healthcare professional may recommend that you monitor blood glucose especially when you are started on insulin or other drugs increasing insulin secretion. You prick your finger with a small needle and test a drop of blood using a device called a glucometer. Your healthcare professional will tell you when and how often you need to check your blood sugar. The following terms are used to describe glucose measurements taken at different times of day:

Fasting

Checking in the morning after an overnight fast, when your blood sugar is lowest

Pre-meal

Checking right before a meal to see how much your levels change when you eat

Post-meal

Checking two hours after a meal when your blood sugar peaks

Keep in mind that a blood sugar check you perform yourself is not the same as the HbA1c test performed by your healthcare professional and the results cannot be compared.

Recording your blood sugar

Checking your blood sugar gives you a snapshot of your levels at a particular moment. Recording these measurements will show you your progress over time.

Accurately recording your blood sugar – as well as what you eat, when you exercise and emotional factors like stress – will identify the causes of unusual peaks and dips. This will help you to improve your diabetes management and avoid long-term health complications.

"I am a slow learner when it comes to numbers - but I promise you, I do what I can."

-Eva Deigaard Lepri

Tips for monitoring your blood sugar

  • Set a routine: Test and record at the same time each day so you remember to do it and can keep your records in a convenient place
  • Record immediately: Don't put it off thinking you will remember the results later – you probably won't!
  • Be honest: Record everything your healthcare professional tells you to: snacks, beverages, carbohydrate content and the exercise you do. An accurate picture of your progress will help you avoid health complications
  • Stay vigilant: Learn to spot trends, such as high blood sugar after high carbohydrate meals or reduced levels after physical activity
  • Keep learning: A blood sugar reading on its own is not a sign of success or failure – it's an opportunity to learn about the factors that impact your blood sugar control and how you can manage them better in the future

There are many tools available to help you record your measurements, including diaries and smartphone apps. Talk to your healthcare professional about which is right for you. You can also visit our Support section for other tips and techniques for managing your diabetes.

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References
  1. Good to Know: Factors Affecting Blood Glucose. Clin Diabetes. 2018;36:202.
  2. Renard E. Monitoring glycemic control: the importance of self-monitoring of blood glucose. Am J Med. 2005;118:12s-19s.
  3. American Diabetes Association. The Big Picture: Checking Your Blood Sugar. Available from: https://www.diabetes.org/healthy-living/medication-treatments/blood-glucose-testing-and-control/checking-your-blood-sugar. Last Accessed: December 2021.
  4. NHS UK. Hyperglycaemia (high blood sugar). Available from: https://www.nhs.uk/conditions/high-blood-sugar-hyperglycaemia/. Last accessed: December 2021.
  5. NICE UK. Type 1 diabetes in adults: diagnosis and management. Available from: https://www.nice.org.uk/guidance/ng17/ifp/chapter/testing-your-own-blood-glucose-and-target-levels. Last accessed: December 2021.
  6. American Diabetes Association. Standards of Medical Care in Diabetes—2012. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3632172/. Last Accessed: December 2021. Diabetes Care. 35 Suppl 1:S11-63.
  7. Diabetes UK. Checking your blood sugar levels. Available from: https://www.diabetes.org.uk/guide-to-diabetes/managing-your-diabetes/testing. Last accessed: December 2021.
  8. Kirk JK and Stegner J. Self-monitoring of blood glucose: practical aspects. J Diabetes Sci Technol. 2010;4:435-9.

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