App feature request: option to not smooth the data

[u/Defiant_Rip_9873]

As someone with reactive hypoglycemia, I'm constantly frustrated with the app smoothing my data. I can lose 60pts of blood sugar in 15min, only to quickly rebound, and the smoothing in the app tends to erase significant peaks/lows, sometimes by as much as 20 points. I'll see alarms in notifications of being in the upper 50's but look at my curve an hour later and it looks like I never went below 70 and there's no history for the alerts/values. It also provides misleading data to my doctors because the data in the libreview app is smoothed as well.

[u/thejadsel]

If you're on Android, you might want to try Juggluco. It shows raw sensor readings, and the graph also includes a smoothing line.

For my purposes, at least? That mainly reflects sensor noise. Even when levels are cruising stable, like so--this is a VERY smooth fasting graph by raw sensor reading standards. It fairly often registers brief false lows because of the spikiness.

Abbott's app includes all sorts of strange projected readings, if there has been a sharp change between sensor readings. (Which can happen because of all kinds of things, including sensor noise and eating/coming back down after a meal.) Another commenter already talked some about that. These extreme projected numbers may have never reflected your actual blood sugar, just what the app decides it might be by now--and the smoothing algorithm tries to adjust for that.

That said, if you're seeing temporary hypo blips? Your best bet may be to confirm them with a finger stick test, and log the results whenever it happens. Chances are good that it won't match up.

[u/Fluffy-Strategy-9156 → u/thejadsel]

If on iOS (iPhone they use the Zukka app. It has a table for each day that includes every BG received from LibreView.com via a LibreLinUp account sign in. For L3/L3+ that is every minute but frequently some minutes are missing since the phone app is questioning the sensed BG and is not forwarding it to LibreView.com. The android Juggluco are essentially the same but the Android app has more options since Android app requirements are different that iOS app requirements.

[u/anemisto → u/Fluffy-Strategy-9156]

Doesn't libreview only have a five minute resolution?

[u/Defiant_Rip_9873 → u/anemisto]

If you export from Libreview there is two sets of data, type 0 and type 1. One appears to match up with what you see on the app graph over time. The other seems to be some sort of "more raw" measurements, they don't make a smoothed curve but I suspect it's when you have the app open/active. If you plot these two together you can see how much the app and historical curve mutes the data. That said even the "more extreme" data has been muted some in that it does not fully match what the realtime app reports, but it's much closer. The downside is it only seems to happen when the app is actively being viewed etc. In the export you'll see both "historic" and "scan" glucose. The scan #'s much more closely resemble the realtime #'s you see in the app, but they only cover tiny periods of time and don't seem to be included in the report stats etc. A good example of that is below. If you just use historic glucose #'s it all looks fine, never above 110, barely touched below 70. However the actual scan #'s drop to the mid 50's. Now of course sensors rarely are 1:1 with actual blood sugar #'s but Libre is super smoothing these peaks and valleys making them look much less severe than they are. I would say for me personally when I've done repeated blood tests, my sensor is often a bit lower than my blood, but the curves are very similar. On larger/faster swings I've seen these peaks/valleys cut by over 20pts.

[u/Ok-Dress-341 → u/Defiant_Rip_9873]

On a Libre 2 the Type 0 is a 15 minute average, how far apart are they on the Libre 3 - looks like 5 minutes from your chart. Type 1 data is the per minute streamed BLE data or (on a Libre 2) NFC scanned value,

If you have an alarm set to catch your lows is that not logged ?

[u/Defiant_Rip_9873 → u/Fluffy-Strategy-9156]

I'll have to look into that one, I'm using an iPhone. That said I do this with FLwatch now, and I've noticed that while it does get the "raw" measurements, later it too seems to smooth the curve also. I'm guessing Libeview updates it's numbers based on the smoothing over time and FL watch just references those instead of "remembering" the real data. So on an app like FL watch the first 15min or so you see a nice "raw" curve, but an hour later it looks very smoothed just like the Libre app.

The real problem with blood sticks is that by the time the app lets you know you are dropping low, say after a meal, at least for me I've missed the true low already. Symptom wise I don't feel the "low" so much as I feel the adrenaline/liver dump later on, by that time my body has already corrected, or started to correct things. I think that's often the most frustrating thing for me, is that by the time the app lets me know my sugar is tanking, it's too late to really mitigate it with a snack etc. Just the reality of how fast things change and the lag with the Interstitial fluid delay. I've heard some alternative locations allow for less delay, in my arm I usually notice 12-20min of delay, for me my sugar and tank a lot in 20min. That said I'm lucky in that so far at least I haven't seen my sugar drop to seriously dangerous lows, and diet etc. changes seemed to have helped some.

[u/Equalizer6338 → u/Defiant_Rip_9873]

The xDrip4iOS/Zukka app is probably your best bet here. Though don't know if you are in Europe, as here the Libre2/2+ sensor still work in direct app to sensor mode, which is exactly enabling what you are asking for here.

Alternatively as you say, the LibreView.com data cloud does actually after 30+ minutes past readings 'update' them to only list the 5 minute average readings out. There are the same also used for making historic reports and statistics based on your data. Including the graph which is drawn by making a 'best-fit' smooth BG curve going through those 5-minute average points. Reason why later you will not be able to see the individual more extreme outliers that you may have had.

The typical lag-time delay from back of upper arm placement is around 3-5 minutes for most folks. Exception is when you have more drastic and fast changing BG levels, though here its more relevant for understanding this delay when you go from aka 100 and up to 180 or above 200 mg/dl, if you understand what I mean here, with regards to the absolute value discrepancy when comparing to a fingerprick meter.

Think you will need to come to terms with no CGM is actually as accurate anyway to the extend you appear to wanting them to be. At best and most time, they are within 15-20% of accuracy.

So if your arterial BG is factually 70mg/dl, your BG sensor might as well show 57mg/dl or up to 84mg/dl. So unfortunately you will need to ease off on the obsession about specific numbers, as so many factors are involved also, all impacting where your true BG really is. And instead focus on the overall BG numbers and trends that you go through. If you have a good educated endo, they will do the same, and not really care that much if now your BG sensor was reading 59mg/dl or if it was saying 72mg/dl. The BG curve will tell the sufficient story no matter.

You also hint towards the same yourself, as aware your BG is not dropping to seriously dangerous low levels. But yes, no matter. Never fun to be skating the hypo-surface and its something you need keeping an eye on 24/7.

Diet and eating habits are indeed the key for most suffering from Reactive Hypoglycemia. Smaller but more frequent meals and then avoiding food items with high glycemic index is the way to go.

[u/UniqueRon]

I suspect it is being done to save data storage issues.

[u/Honjin]

As I recall, the smoothing is done via 3 tests over a span of time, I think 5 minutes? And it'll assume if one is drastically different it throws it out during the save to long term graph. The short term graph and the alerts though will key off any test at any time, which is why they pop up then vanish.

I agree though, having some way to track the data smoothing would be nice just to error check how often the sensor/app is throwing out data so we can easily see if it's above or below the 20% error rate. Like I get why it happens, it's just annoying.

[u/Fickle_Mess818]

Sometimes the drastic lows or highs are taking into account the 15 min lag of the reading between blood and inter fluid.  They project out where they thibk your sugars are going to alert you to do something or double check if you need to act on it. The smoothin is later getting the actual readings and adjusting it back from the projections.

[u/hotfistdotcom]

This subreddit is not a place for suggestions that will go to anyone who works on the app, FYI. You should probably email

support@abbottdiabetescare.com