Quin displays blood sugar in the app using the default unit for blood sugar set on your iPhone. This is to ensure that Apple Health and any other diabetes app you use on your phone will all use the same unit.
To change your unit, you must change the default value in Apple Health using the following steps:
Open Apple Health
Tap on Browse
Scroll down and tap on Vitals
Tap on Blood Glucose
Scroll down to the bottom and tap on Unit
Tick the appropriate unit
Go back to Quin
That's it! Quin will automatically use the updated unit and convert all blood sugar into the new unit.