Wednesday, December 14, 2011

The trouble with 20%

Meter accuracy (or lack thereof).


I think I speak for the entire DOC when I say it makes our collective butts itch. It still makes me want to scream that a 20% accuracy is acceptable.

The problem for those of us that have wee ones is that when a high number pops up on that ol' inaccurate meter, there is a greater margin of error.

Take, for example, what happened the other night. It was 1 am. Elise was 352. I decided to check again. This time 305. That's almost a 50 point difference!

And what does 50 points mean to Elise? Well, just for chuckles, I popped both numbers into the PDM, and there was a difference of .2o units of insulin. Not a big deal if you're an adult.

Kind of a big deal if you're 4 years old. When I did the math, I figured out that .20 units of insulin drops Elise by 50. Elise's target at night is 140. That means that if I corrected for the 352, Elise could end up at 90. Not a good number for the overnight. Me no likey.

And I'm not even taking into account the fact that Elise tends to drop at about 6:00 am, especially when she has received any sort of correction in the night (we're still fiddling with the numbers and trying to find what works). She has been in the 50s a number of times in the 6-8am time period after a correction that has taken place over four hours prior. If we don't have to correct her, it's pretty smooth sailing.

The problem as I see it is this; the higher the blood sugar, the more insulin you give. And the higher the number on the meter, the bigger the margin of error. To me, that's just dangerous when it comes to our tiny kiddos with D.

When I get a high reading, I shouldn't have to check again (as we all know, those suckers are expensive). And I shouldn't be worried that I'm giving Elise too much insulin, causing me to lie awake all night, fighting the urge to check her every 30 minutes. Shouldn't we be able to trust our technology?

For the record, I corrected using 305. And she woke up just fine.


  1. I find this to be infuriating, too...we are lucky that our insurance covers enough test strips so that when we get wonky numbers we can double check, but I had to fight for those test strips and utilized the fact that the accuracy isn't 100% so for a small child I needed to be able to double check numbers that were extremely high (or low). Pisses me off that I have to further go into the cost of a trip to the ER-vs-a few extra test strips to get coverage so that I can safely dose the little dude. This is one area that I wish were getting a bit more attention, because truly if we're using finger pokes to calibrate the CGM and the finger pokes are off than how accurate will the CGM be? Sorry...I could go on and on.
    I am glad you found a way to keep her from going too low that time, hopefully tonight no 300's will pop up and no correction will linger later effecting early AM BG #'s. We've found for Isaac that a half correction at night with an increased basal for 2hrs works better in combating highs and not having later lows. But again YDMV :)

  2. I thought I was alone for years with this 20% accuracy rate. Just think what that means if you get a reading of 50? I am glad you bright this up. Just don't look at the temperature guidelines on your meter. I think that is scarying me more and more in the winter.

  3. Blerg. No fun :(

    I hate that 20% deviation allowance. HATE IT!

    I have heard this before about the Omnipod's PDM. I've seen several blog posts where people retest with a different meter before correcting.

  4. I so wish we could trust our technology! That number that pops up is just a moment in time but oh so important.

  5. This pisses me off so much. As you said when it comes to kids with larger ISFs this can mean serious consequences. FDA needs to fix this asap!

  6. UGH is right. it's so freaking ridic. glad things worked out this time, but yeah: UNSAT.

  7. Amen. All A1Cs should come with a 20% caveat!

  8. 20 percent deviation is unacceptable, but it's all we've got to work with. If trending low, I do three-quarter corrections; sometimes half corrections overnight. If trending high, I give 20 percent more correction but only if I'm sure I can stay up. I would err on the side of caution like you have done. Glad it worked out. Unfortunately, we do have to factor in the exhaustion factor before deciding how much correction we are going to give.

  9. Yes yes yes yes yes. 20% is huge and it's not okay when we are dealing with our lives!!!!


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