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Wildly Inaccurate Index BPM and Bad Fit Issues

I have recently discovered I have high blood pressure and the Index BPM seems like it would be the perfect solution for helping me keep an eye on my condition. I already have a Garmin scale, watch and bike computer as well as enjoying the Garmin Connect app for keeping all my health metrics in one place. However, the Index BPM is highly inaccurate (+25-35/+15) and has issues fitting (which may or may not be the cause of the bad readings).

Accuracy: I have a cheap $25 monitor that has been reading a bit low compared to readings at the doctor’s and so decided to buy the Garmin version. The Garmin one continually shows MUCH higher readings and bumps me from you-need-to-keep-an-eye-on-your-BP to the you-need-to-go-to-the-ER category. The results were so shocking I went straight to Walgreens and bought a $100 BP unit to compare results. The Garmin unit is very high. I also took all 3 units to my doctors and we ran several side by side tests. The cheapo $25 one showed -10 lower results. The $100 Walgreens one matched with the doc's equipment and the Garmin was +25-35/ +15… It is way off.

Fit: The Garmin’s cuff is, for some reason that I can not understand, delineated by hard plastic strips. So rather than having a strap that you can adjust to any size you seat the metal bar between one or another of the plastic strips. In my case seating it in one position (the 2/3 bit in Garmin’s drawing) means in its tightest position the cuff is too lose and the unit will slip from my arm and fall off. On the other side of this position (position 1 on Garmin’s diagram) the cuff is far too tight. I can not slide it on to my arm and if I force the unit to strap to that position it cuts circulation off to my arm immediately. I really can not understand what they are thinking here as the gap between the two positions is quite large. By the way, maybe I’m doing something wrong, my upper arm measures 39cm (Garmin says the Index BPM should fit between 22-42cm) but actually trying to fit the cuff puts me in between the small and medium positions of Garmin’s sizing for the cuff.   

If I force the hard plastic area of the cuff into the metal band and then fold the cuff at that point the fit is good but as soon as I remove the unit the cuff’s velcro sticks together on both sides of the plastic strip and the only way to refit the unit it to completely start over (so no quick slide-the-unit-on and do a test).

In any case, whether the unit is way too tight, way too lose, or in the position where the plastic strip is folded I get the exact same far too high readings (in the “too lose” position I also often get an “E3” error).

One last note which might also be part of the problem, the velcro seems comparatively weak. The other unit’s I have on hand have very strong velcro on their cuffs. The Garmin velcro does not feel very grippy. The entire time the unit it testing the velcro is crackling and popping as if it never quite locks in place. No amount of smoothing the connection or trying to force the pieces together changes this. The other two BP units I have crackle for a minute as the velcro sets but then lock into place as the pressure of the cuff ramps up.

Calling customer care was not a solution for the issues. I was told that “this probably wasn’t the unit for me” and so have started a return for it.

  • After two days of purchase I started getting consistent results by lying on the bed on my back with my arm loosely next to my body. In that case, out of 50 trials, all 50 matched the reference BPM.

  • I have the cuff set so that I can slide it freely on my arm. Then I don't manipulate her in any way.

  • Former Member
    0 Former Member over 1 year ago

    Seems like poorly designed. Same experience - readings are NOT accurate at all.
    Returning...with no firmware updates this will not improve

  • In my case I do not adjust the Velcro at all. I set it one time and leave it. It is initially loose enough to slip over my hand and bicep. Upon activation, it tightens up enough to get an accurate reading. It's not like other cuffs where you're supposed to start out with it snug. Compared many times with my Omron monitor and there is usually very little difference. Mentioned this in another post - First impressions - Index BPM

    I might be the odd user that is happy with their Index BPM, but this after all is a forum, so I except complaints to outweigh approvals. I think anyone with an issue should contact Garmin Support for assistance and/or exchanging or refunding the device.

  • My arm adjustment is in the middle of the velcro band (between the 2 red lines) I simply set it up once, bend/fold the velcro in 2 and never touch it ever again. I set it up so that it is loose enough for me to slide it up/down my arm when deflated, but tight enough so that it can inflate properly. This way, I set the band once and don't need to change it ever. Even though the metal bar is in the middle of a velcro band, it works well for me.

  • Are you still getting accurate readings while lying down?

  • During the time since the purchase, I have learned to use the device exactly according to the instructions, and after eliminating unnecessary errors on my part, the measurements are being carried out absolutely accurately.