I've been using a One Touch Ultra 2 glucometer ever since I was misdiagnosed as Type II in 2010.
I'm on my second month of using the G4 and for the past few weeks I've noticed something very odd:
I always wash my hands before testing my blood glucose and used to correct my G4 when it was off by ~20%.
But I tested once when my G4 read 210 and my One Touch Ultra 2 said 74. I couldn't believe it, so I tested again and it said 202. I tested one last time and it said 194... so that 74 was just completely wrong!
Even worse, if I had believed it and corrected my G4, that would have really messed up the algorithm.
Ever since them I've been a bit weary when my G4 seems to off by a lot.
The next week I woke up with a 92 according to my glucometer but my G4 was in the ~150s, so I tested again: 159.
Just now my G4 is at a steady 155, but I tested after lunch and my One Touch Ultra 2 said 97... re-tested: 152.
Has anyone else ever experienced this?
What is odd is that I would expect a glucometer to sometimes report a number that is much too high (if I just used Purell or have alcohol or sugar on my hands or something) but I don't see why it would report a lower value!
Anyway, later this month I'm starting on a Minimed Revel 523 pump, which uses the Contour NextLink glucometer. My insurance only has a deal with One Touch Ultra 2 so I was stuck with them until I start using the pump (and then they will finally cover the Bayer test strips). Although for that same reason I'm going to have to switch from Novolog to Humalog (which I am not looking forward to) because my insurance switched their contracts from 2013.
It makes me wonder how often it was wrong back in my pre-CGM days, when I would eat to counter a "low number" and it would skyrocket (and I wouldn't understand why!).
Now I'm very weary of "correcting my G4" unless I'm very sure it's wrong!
I have noticed differences between my glucometer (built into my OmniPod PDM) and my CGM. At first I thought the CGM was wrong. Now if there is a large difference, I hit done on the PDM (so I don't correct on a potentially incorrect reading) and test a second time. So it's not just your meter that is making mistakes. My CDE continously reminds me that the meters have a ±20% margin of error. And to anticipate your response, that doesn't give me a warm, fuzzy feeling, especially if I am in the forties or fifties.
I agree with making sure your hands are completely dry before you test. If you still have problems after that you should call LifeScan as you may have a problem with either your glucometer, strips or both.
I do think it is wise to test twice if your meter number is way off from your CGM. I have an Accuchek Aviva, and have not had the problem of numbers that far off, but last week, when I had the bad low, I tested twice. My hands WERE clean and dry, and one reading was 49 and the other was 48. That was pretty convincing. The Dex was 66 or something like that, but I figured either way, I was low (especially when I figured out what I had done), so I went ahead and treated. So I think it's important to consider what might have caused a certain reading, too. Because we CAN get ourselves in trouble!
ive been having a lot of trouble lately with my one touch ultra. finally called animas today (it's linked to my ping pump) and they're sending me a new one. i don't use a cgm, but i've had some crazy fluctuating readings on the meter. i've ended up really low because i trusted the meter when i truly wasn't as high as it said i was. i know this because i've given myself a correction bolus several times and gone low. just this morning i tested 3 times within a few minutes: 88, then 217, then 71! last night i got 388, then 410, then 347! of course i gave myself a correction, but not believing the meter i gave myself about 2/3 of what i should have given myself based on the 347 number, and i still went low! so frustrating!
I have 5 different FreeStyle Lite meters. All compliments of the Abbott company since my insurance company requires all D's to use their strips, unless they are on a pump that uses a different strip/meter combination. But if I were to take a single drop of blood and use it on a strip on each of the 5 meters - same drop of blood - since it uses very little, the readings would all be different. I had this happen with 3 meters the results were 62,76 and 80. My CDE said just choose 1 meter and only use that 1. It was good advice and that is what I did, but I have since gotten the G4 and I have never had that big of a difference between what the Dex says and what the meter says. The meter invariably reads higher than the CGM but it hasn't been 136 points off that would really piss me off.
keep in mind these are only tools and they will do what they will do. Everyone else has give the same insight I would give. A carpenter once told me "measure twice, cut once". some times I will measure three times, however, I always use the same tape (tool). Check all of the dates, batteries,etc. Remember with anything the variables are Person, machine, material, method, and environment. Eliminate all of the ones you can.
Thanks for the feedback, everyone!
I'll make sure my hands are extra dry (as that would explain getting a lower number) and maybe I'll try using my wife's old One Touch Ultra 2 from when she had gestational diabetes (I always joked that I got post-gestational diabetes since my diabetes appeared 6 months after we had a baby) to see if that makes any difference.
Turns out my One Touch Ultra 2 was on the fritz:
I was calibrating my G4 (with the double-testing where it doesn't tell you what level you're at until the end) and my first number was:
152 (so I entered that in my G4)
then I tested for the second calibration:
so I entered that (my G4 now said 205) and I tested again:
I tested again 25 minutes later to make sure:
So I tried my wife's old One Touch Ultra 2:
222 (that at least makes sense so I enter it into my G4 to try to salvage the calibration)
10 minutes later my G4 beeps at me asking to calibrate with 1 drop (and it doesn't show me my current glucose level... which it's never done before! I like to think that it realized that something was off and wanted me to remedy the situation) so I test again with my wife's old glucometer:
222 (so I enter that and the G4 seems to be happy: saying 214)
I should have been more weary of the 152 since I just ate... and I really should have known better after the previous weeks of iffy readings, but it was after 24 hours of travelling and I was a bit out of it!