What is A1C?

A1C is a measurement of your average glucose levels over the past three months.1,2 It’s used by healthcare professionals to measure how well your diabetes is being managed and is given as a percentage.1


The goal for most people with type 1 or type 2 diabetes is an A1C below 7%.3

A1C also helps diagnose diabetes2

An A1C higher than 5.7% and lower than 6.5% is considered to be in the pre-diabetes range,
while an A1C of 6.5% or higher is in the diabetes range.2

How is A1C measured?

When glucose is in your blood stream, it enters your red blood cells and attaches to a protein called “hemoglobin”. A1C is a measurement of the percentage of hemoglobin in your blood that’s attached to glucose.1,4

A1C and glucose variability

No matter your A1C, it’s possible to spend a significant amount of time outside of your target glucose range (which is where you and your diabetes care team would like your glucose levels to be).5-7

Revealing a more complete picture of your glucose variability  



Giving you actionable insights into your glucose trends and patterns (i.e., you can see how certain lifestyle factors, like food or exercise, impact your glucose levels)

Allowing you and your doctor to make better-informed treatment decisions


The FreeStyle Libre family of products is shown to help patients with diabetes reduce their A1C.8,9


  1. Mayo Clinic. A1C test. Available at: https://www.mayoclinic.org/tests-procedures/a1c-test/about/pac-20384643. Accessed December 7, 2021.
  2. American Diabetes Association. Understanding A1C. Available at: https://www.diabetes.org/a1c. Accessed December 7, 2021.
  3. Diabetes Canada Clinical Practice Guidelines Expert Committee. 2018 clinical practice guidelines: targets for glycemic control. Can J Diabetes 2018;42:S42-S46.
  4. American Diabetes Association. A1C and eAG. Available at: https://www.diabetes.org/diabetes/a1c-test-meaning/a1c-and-eag. Accessed December 7, 2021.
  5. Dunn TC, et al. Development of the likelihood of low glucose (LLG) algorithm for evaluating risk of hypoglycemia: a new approach for using continuous glucose data to guide therapeutic decision making. J Diabetes Sci Technol 2014;8(4):720-30.
  6. Beck RW, et al. The fallacy of average: how using HbA1c alone to assess glycemic control can be misleading. Diabetes Care 2017;40(8):994-99. https://doi.org/10.2337/dc17-0636.
  7. Kovatchev BP. Metrics for glycaemic control – from HbA1c to continuous glucose monitoring. Nat Rev Endocrinol 2017;13(7):425-36. https://doi.org/10.1038/nrendo.2017.3.
  8. Kröger J, Fasching P, Hanaire H. Three European retrospective real-world chart review studies to determine the effectiveness of flash glucose monitoring on HbA1c in adults with type 2 diabetes. Diabetes Ther 2020;11(1):279-91.
  9. Campbell FM, et al. Outcomes of using flash glucose monitoring technology by children and young people with type 1 diabetes in a single arm study. Pediatr Diabetes 2018;19(7):1294-301.





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