XDrip+ Now Displays GVI and PGS

With the latest nightly release of xDrip+, the app now calculates GVI (Glycemic Variability Index) and PGS (Patient Glycemic Status).

Basically, the GVI measures the length of your CGM track over a specific period of time. The longer the length of the track, the higher the glycemic variance.

PGS basically measures your GVI+ mean glucose+ time in range and presents it in a single number that is closely related to your glycemic state, or control.

These numbers are soon to become the measure of diabetes control, replacing SD and CV.

A good primer on the subject can be found here:

The 23Feb nightly xDrip+ release can be found here:


@docslotnick, this post is really outstanding!

I just read your healthline link: it makes total sense, and is very intuitive. A great concept.

I am excited about discovering this new (to me) concept! I can’t wait to play with it.

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Wow, fascinating!! I’m really thinking that once we set up openAPS again, we should switch Samson to an Android device so he can use xDrip+ and all its attendant benefits (longer transmitter life, extra info, etc. etc.)


It occurs to me, btw, that this illustrates perfectly the power of the opensource concept.

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Interesting. Also makes me feel good :wink: since xDrip+ reports that for the past 90 days, my GVI was 1.16 and my PGS was 34.70. Along with my “too low” A1c of 5.6% (thanks, endo :roll_eyes:) I’m sorta on track…?


Really awesome! Based on your GVI, your track is barely longer than a straight line, that is amazing!

Awesome, just downloaded it! I posted this on another forum, but on a related note does anyone know what ideal numbers should be for voltage A, B and resistance? I just switched to a new transmitter and surprised to see the numbers are similar to my almost 6-month old transmitter which I feared was near sudden-death. The numbers are 315, 304 and 623 respectively. Did I get a dud? Just received the new transmitter last week from Dexcom.

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Well, there’s likely some missing data, so in all likelihood those numbers are not perfect… Share has all the data., though - I wish there was a way to reload Share data into xDrip+

@Scotteric According to JamOrham, the xDrip+ developer:

Lower internal resistance means it can push more power and is generally better, that figure can be used to assess some battery health but more usefully the quality of any battery replacement. We mark >1400 resistance as bad, >1000 as questionable and <750 as great. voltage a < 300 is marked as bad, voltage b < 290 is marked as bad

Wow thanks, I wish I didn’t give up on my last transmitter then, I could’ve gotten much longer out of it!

@Michel. But if you noticed in the article that this concept was put forth by Dexcom!
Also, I think that these metrics are also available in Nightscout reports. But I don’t know how you would access them as I don’t use Nightscout.

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@Scotteric BTW, xDRIP+ will give you a heads up about a week before it thinks the transmitter will fail, so you won’t be caught by surprise.

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This is really good to know! Can I expect to get ~6 months out of a transmitter?

Absolutely! You might want to look at this thread:

In addition to what @docslotnick mentioned, the shelf life of the transmitter may make a difference. The first one of the batch appears very long lived, but the second one may be shorter by quite a bit.

The thread @docslotnick quotes discussed that aspect as well.

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We only order them one at a time in Canada, so no problem there!


Did anyone have trouble after installing the latest releases? It was working fine until I restarted my phone and could not get xDrip to connect. I tried the OB1 collector which worked, but then I was getting notifications every time there was a new reading every 5 minutes on my watch! When I shut OB1 off I would consistently get readings every 10 minutes instead of 5. Then my phone Bluetooth started shutting off randomly. I deleted xDrip and returned to the release I had been using (Nov 17, 2017 I think) and the problems went away. I am even able to use OB1 without watch buzzes every 5 minutes. What does OB1 do btw?

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I also am really thankful that Sulka and Kimberlie did add GVI and PGS to the stats.

While GVI can be calculated directly from the CGM values, PGS highly depends on the target range.

What range would you take (or did they take) for the “<35 excellent glycemic status (non-diabetic)”? A non-diabetic I would presume? 70 to 110?

That is what I would do. @docslotnick, do you have any thoughts on thsat?

oh wow…I just glanced at the Healthline write up…it makes perfect sense. If you research the background of the founders for Dexcom, you’ll see that they are data guys, I think from finance/stock market.

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