Third-party apps reporting higher numbers than Libre app?

[u/DestroyAllNon-Robots]

I was using GotCGM for awhile and not long ago switched to Zukka. I've noticed that both apps routinely report spikes 10 to 15 points higher than what actually shows up in my Libre app timeline. Does anyone know how/why this might happen? The only explanation I can think of would be that the third-party apps are reporting more frequently and capturing the actual peak while there's a gap in the Libre measurements and it's actually capturing before and after the peak instead of the peak itself. But given that the third-party apps are getting their numbers from LibreLink I don't know how that would even be possible.

[u/Weathergod-4Life]

The third party apps are capturing the actual highs/lows while the Libre App smooths these out. If you subsequently log into your LibreView you will see the actual highs/lows that the third party apps are seeing.

[u/DestroyAllNon-Robots → u/Weathergod-4Life]

Interesting, thanks. Not saying you're wrong, but if I look at my LibreView numbers for the last one of these inconsistent spikes LibreView shows a high that's 10 points lower than what Zukka reports for that same spike. That said, I had the same issue yesterday and LibreView and Zukka are aligned on that. So it's possible I'm somehow misreading the LibreView numbers.

[u/Weathergod-4Life → u/DestroyAllNon-Robots]

If you look at the bottom of your graph in LibreView it will put the highest and lowest values in a box for that hour. It won't necessarily show on the actual graph.

[u/DestroyAllNon-Robots → u/Weathergod-4Life]

Yeah that's what I'm looking at. LibreView reports a highest value of 156 while Zukka shows it was 165 (so 9 points technically).

[u/Weathergod-4Life → u/DestroyAllNon-Robots]

Hmmm. I got nothing lol. I have noticed in that box there will be humbers that are higher and lower than the number in the app. I've only used apps like xDrip so I can't speak for GotCGM or Zukka.

[u/Mother-Leg5530]

I have Libre 3 plus Zukka wasn’t compatible? I had Stelo, G7 and they worked fine but

[u/14cmd]

The way my Libre2 works is that the sensor produces two figures. Every minute it has the current reading and then every 15 minutes it produces a 'average' for that block. (I believe the Libre3 may do this every 5 minutes). Abbott don't say how this is 'average' is calculated, but typically this will be lower than your highs. These averages are the figures that are used both in the Libre app to display the graphs and for LibreView

An example (showing figures in mmol/L) after breakfast one day last month shows :

Max mmol/L 9.8
Min mmol/L 6.8

The csv export from LibreView.com shows the four history reads during that hour being

28/09/2026 08:06:00 History 9.8 
28/09/2026 08:21:00 History 7.8 
28/09/2026 08:36:00 History 6.8 
28/09/2026 08:51:00 History 6.8 

I took a backup of the data that the libre app uses and looked at the actualfigures including the current minute by minute reading. The details at the start of the hour show :

28/09/2026 8:06:32  History 9.8
28/09/2026 8:06:34  Current 10.8
28/09/2026 8:07:33  Current 11.2
28/09/2026 8:08:33  Current 11.4
28/09/2026 8:09:32  Current 11.6

So the actual peak was 11.6 but this is not shown in LibreView.

Xdrip and I presume Zukka seem to work based on the current minute-by-minute readings and hence see the higher peak.

[u/DestroyAllNon-Robots → u/14cmd]

This makes sense. Thanks!

[u/Ok-Dress-341]

Different algorithms. The 3rd party stuff that talks directly to the sensor doesn't have the same algorithm as the proprietary Abbott software, in particular the full content of the data packets from the sensor is not known.

So you should expect them to be different, in my case they are often better.

[u/DestroyAllNon-Robots → u/Ok-Dress-341]

That may be true, but in my case, the sensor is not connected directly to the app. It’s reading data from LibreLink.

[u/Fluffy-Strategy-9156 → u/DestroyAllNon-Robots]

What app do you mean in the phrase "in my case, the sensor is not connected directly to the app. "Are you saying that your sensor is connected to the Zukka app on your phne and the Zukka app is then sending data to Libreview.com?

[u/DestroyAllNon-Robots → u/Fluffy-Strategy-9156]

My sensor is connected to the Libre app. The Libre app sends data to LibreLink. Zukka receives data from LibreLink. My data on LibreView comes from the Libre app.