FAQs Logbook

How does the Estimated A1c work?

The Estimated Hba1c does not apply to US residents


How does the app calculate my Estimated A1c?

First, the app checks if you logged 21 blood sugar values in the last 7 days (including the current day). If that’s fulfilled, it checks if you logged those values on at least 4 out of the 7 days. That’s important because otherwise one could log 21 values in just 1 day and get an estimate that’s most likely far away from a lab result.


If the two criteria above are fulfilled, the app takes the average of your blood sugar values, puts it into a formula and calculates your Estimated A1c. You don’t need to crunch any numbers, the app does it all for you!


Which data is taken into account?

The Estimated A1c is calculated using your logged blood sugar values (not CGM or sensor data). If you have 21 blood sugar values logged on at least 4 of the past 7 days (including the current day), then the app can also take into account the past 90 days of data. The app looks back at your past data until it detects a “gap” in it. A gap in your data means that there were more than 2 days in a row where you didn’t log any blood sugar values. If a gap is detected, then no further values are taken into account.


Why is my Estimated A1c not displayed?

Without enough data, an estimate can’t be calculated and displayed. That’s when “-” is displayed. If you tap on the Estimated A1c field on the home screen you’ll see a detailed explanation with information on how much progress you’ve already made. Keep feeding blood sugar values into your logbook and you’ll have your Estimated A1c in no time.


It could happen that from one day to another your A1c disappears. That’s because the app always looks back at the last 7 days, including the current day, and checks if you have 21 blood sugar values logged on at least 4 out of those 7 days. It can happen that yesterday those criteria were fulfilled but today they are not. Just keep on logging and it will come back :)


How can I make the estimate more accurate?

The A1c displayed in the app is an estimate. It could differ from your lab result and is not a substitute for it. But there are things you can do to make it as accurate as possible. As always, measure as often as you can. Yes, it’s annoying and sometimes can be a pain (literally in the finger!), but it helps you to get a clearer picture of your blood sugar. Another thing you could do to get a more accurate estimate is to measure at different times during the day, for example: morning, lunchtime and dinnertime.


Why is my A1c not changing??

The value doesn’t change with every new blood sugar value you enter in the app. It might be that your values are so stable, that a new value simply doesn’t impact your estimate.


What does the color coding of the icon mean?

The Estimated HbA1c has three different ranges. An Estimated HbA1c of 6.5% or 47.5 mmol/mol or below is considered very good, and the icon on the eHbA1c widget will appear green. A medium eHbA1c, which falls between 6.5% and 7.5%, or >47.5mmol/mol and 58.5mmol/mol, will be indicated by an orange icon. If the eHbA1c is above 7.5% or 58.5mmol/mol,, suggesting that diabetes management might need attention, the icon will be red.


Please note that this information is solely intended to explain the meaning of the estimated HbA1c ranges and their corresponding color representations. Please discuss questions regarding your diabetes therapy with your healthcare professional.

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