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HbA1c Conversion Chart
Triangle of Diabetes Care
Time in Range
An important measurement that goes beyond HbA1c
What is HbA1c?
HbA1c is your average blood glucose (sugar) levels for the last two to three months.1
An HbA1c test is used to measure glucose levels by calculating how much haemoglobin in the blood has become glycated (chemically bonded with glucose).1
What is Time in Range?
Time in Range is the percentage of readings and time per day you spend within your target glucose range.
The FreeStyle Libre systems* automatically calculate the percentage of time you spend in, above, or below the target range agreed with your Healthcare Professional.2
This example Time in Range report shows a person who spent 75% of their day in target glucose range.
Images are for illustrative purposes only. Not real patent data.
The FreeStyle Libre systems** help increase %TIR
An independent study published in the New England Journal of Medicine shows that FreeStyle Libre 2 users increased their Time in Range by over 2 hours per day:2,**
- 156 people with T1D ≥16 years with HbA1c ≥7.5% participated in a randomised, controlled study
- FreeStyle Libre 2 users spent 2.2 hours more time in range per day at 6 months of use vs those using self-monitored blood glucose
Time in Range in Action
Why is Time in Range important?
How does Time in Range fit in with your HbA1c?
HbA1c is a great tool for keeping tabs on your glucose levels, but it does have its limitations5
HbA1c reflects your average glucose over the last 2-3 months, but it does not show how often your glucose levels have reached hyper- or hypoglycaemia.5
Time in Range is a complementary measurement for you and your Healthcare Professional to use alongside HbA1c.5,7 And by increasing your Time in Range you’ll see a decrease in your HbA1c.
Every 10% increase in Time in Range = ~0.8% decrease in HbA1c.4
Every hour each day your spend in Range is associated with clinically significant benefits.5
Estimate of A1c for a given Time in Range level based on T1D and T2D studies.4
70% TARGET IS CHOSEN AS IT STRONGLY CORRELATES WITH A1C GOAL OF 7.0%5
Share your Time in Range data with your Healthcare Professional through LibreView₼
You and your Healthcare Professional can get in-depth information about your Time in Range through reports on LibreView₼, our secure, cloud-based diabetes management system.
FreeStyle LibreLink app◊ and FreeStyle Libre 3 app◊◊ users need to create account in LibreView in order for their data automaticallyǁ uploaded to your LibreView.
If you choose to share your LibreView data with your Healthcare Team, they will have access to all your glucose data to help them create a tailored treatment plan for you.
Learn more about Time in Range in our dedicated learning module
HbA1c Conversion Chart
Triangle of Diabetes Care
References & Disclaimers
Images are for illustrative purposes only. Not real patient or data.
* FreeStyle Libre systems refers to the FreeStyle Libre 2 and FreeStyle Libre 3 systems
** The data from this study was collected using the FreeStyle Libre 2 system. FreeStyle Libre 3 system has the same features as the FreeStyle Libre 2 system therefore, the study data is applicable to both products.
₼ The LibreView data management software is intended for use by both patients and healthcare professionals to assist people with diabetes and their healthcare professionals in the review, analysis and evaluation of historical glucose device data to support effective diabetes management. The LibreView software is not intended to provide treatment decisions or to be used as a substitute for professional healthcare advice.
◊ The FreeStyle LibreLinkapp is only compatible with certain mobile devices and operating systems. Please check the website for more information about device compatibility before using the app. Use of FreeStyle LibreLink may require registration with LibreView.
◊◊ The FreeStyle Libre 3 app is only compatible with certain mobile devices and operating systems. Please check our website for more information about device compatibility before using the app. Sharing of glucose data requires registration with LibreView.
II The user’s device must have internet connectivity for glucose data to automatically upload to LibreView.
1. Diabetes UK, What is HbA1c? https://www.diabetes.org.uk/about-diabetes/looking-after-diabetes/hba1c (Accessed: Jan 17, 2025).
2. The international consensus sets the target in range (3.9-10 mmol/L) for adults with type 1 and type 2 diabetes who are not pregnant, not older, or at risk. Consult with a healthcare professional on individual target glucose range.
3. Leelarathna, L. N Engl J Med. (2022): DOI: 10.1056/NEJMoa2205650.
4. Vigersky RA, McMahon C. The relationship of hemoglobin A1c to time-in-range in patients with diabetes. Diabetes Technol Ther. (2019);21(2):81-85.
5. Battelino T, Danne T, Bergenstal RM, et al. Clinical targets for continuous glucose monitoring data interpretation: recommendations from the international consensus on time in range. Diabetes Care. 2019;42(8):1593-16033. Vigersky RA, McMahon C. The relationship of hemoglobin A1c to time-in-range in patients with diabetes. Diabetes Technol Ther. (2019);21(2):81-85.
6. Beck RW, Bergenstal RM, Riddlesworth TD, et al. Validation of time in range as an outcome measure for diabetes clinical trials. Diabetes Care. (2019);42(3):400-405.
7. The international consensus report has been endorsed by the ADA, AACE, AADE, EASD, FEND, ISPAD, JDRF, and PES.
ADC-57252 v3.0
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