Glucose measurement is in mmol/l but it is really in KG/L?

[jboro]

I donwloaded the iOS nrf toolbox. I found that the app converts the glucose measurement to KG/L and not to mmol/l? The reading on the glucometer is in mg/dl so when I multiplied the app reading by 100000 , that is when they are the same. Also the parsed time is late by an hour. Right now I don't have an idea why but I'm checking out the downloaded code. Anyone have an idea why this is an issue?

[Stian Røed Hafskjold]

The bluetooth spec for the glucose service shows that the data can be transferred as both kg/L or mol/L by setting a flag in the glucose_measurement characteristic. See here: developer.bluetooth.org/.../CharacteristicViewer.aspx

The android version of the app converts from kg/L to mg/dL (by multiplying with 100000), OR from mol/L to mmol/L (by multiplying with 1000), depending on which flag is set in the characteristic. There is no conversions other than this going on (like from grams to mol).

However, the iPhone app seems a bit buggy, so it does not check the flag, and treat all raw data as mol/L, and therefore always multiply the raw data with 1000.

This means that your data that is transferred as kg/L (according to the spec) is then multiplied by 1000 to give you g/L (even though the app says mmol/L).

The parsed time seems right though. It corresponds to what is sent in the measurement characteristic.

You can try to download the lightblue app for iPhone to see the raw data in the characteristic. You can read about how to do a "read all" operation here, infocenter.nordicsemi.com/.../ble_sdk_app_gls.html, in step 7.

[jboro]

Hi Stian, thanks for looking into the issue. About the time, I can't seem to get a right reading of the time, both in iOS and Android. I get the readings an hour late. Is it because of the Daylight Saving Time? There is no DST in my time zone right now but it seems like there is DST where the bluetooth device was made. Or it doesnt matter?

[Stian Røed Hafskjold]

I doubt that it is any DST conversion going on in the app, it should just reflect what is given in the data packet. So maybe your glucose device converts to DST before the packet is sent. I will do some more test later, and ask the guys who made the app. Meanwhile, can you please give me the name of the glucose device you are using?

[jboro]

Hi Stian, I'm testing the Accu-chek Connect glucometer. I have used Lightblue before and has indeed helped me. For the time issue, I have resolved it by multiplying the timeOffset by 60 and adding that to the date reading. I think the android version also forgot to add the timeOffset value that's why im also getting an hour late time from there. Might fork a sample from Github and try to add it. Thank you again :)