The Glucose Meter Shuffle.
I have several One Touch meters, a Freestyle one, and a Dexcom continuous glucose monitor that I consult on a regular basis. (Not usually at the same time, but I have been doing multiple checks recently. More on that below.) I also have an Agamatrix meter and an Accu-chek one, somewhere in the diabetes cupboard in the bathroom, only without any strips that aren't expired.
And I have a lot of anxiety when it comes to glucose meters. The variability of these machines makes me crazy in the head, and it caused me a lot of grief when I was pregnant, because my blood sugar goal range at that point was so tight and so specific, and any variability was huge for me. (I shared some samples of wonky results in this post.)
In the last few weeks, I've been doing some experimenting with my meters, inspired by at-home research conducted by Stacey at The Girl with the Portable Pancreas. It's an messy process, which includes testing with several meters at one and trying to grab a photo. It's also messy because it involves the people at One Touch (because they provided me with some spare strips after I spoke with them about my meter issues and I have a running dialog with them about this problem), my insurance company (because I had to work with them to get a partial prescription covered for a batch of Freestyle strips), and my patience (because I'm short on that due to the aforementioned).
So far, I've noticed a few trends: The Freestyle meter almost always runs higher than my One Touch meters. I'm not sure if that makes it more "accurate" or not, but it is consistently higher. Thing is, there isn't a pattern I've found yet when it comes to syncing up with the Dexcom. For example, the photo below has the Freestyle much higher than the One Touch meters, but my Dexcom was at 98 mg/dl with a down arrow, and I felt low. So what am I supposed to trust in that instance? If I go with the One Touch results, I'm potentially treating that number. If I follow Freestyle, I'd happily get in the car and drive at that number.
The One Touch meters are usually close to one another (like in this photo):
But are they close to my actual blood sugar? When I was pregnant, I saw One Touch meter results that seemed lower than I felt, and when I consulted with the Dexcom, I was prompted to recheck. Then I'd see a higher number on the meter. Without the Dexcom, I wouldn't have ever second-guessed my meter. Part of why I wanted to conduct this meter comparison now was to see if I could duplicate those variances and then document them, but I haven't seen the same problems since running these tests. (I know it sounds weird to be frustrated by a lack of problems, but it's like when your car makes a noise when you're driving around town, but refuses to make the same noise when the mechanic is standing there. How can they fix what I can't show?)
I know there is an "acceptable" 20% margin of error, but how would you even know to double-check your meter? This issue matters to me, and it matters a lot. These glucose meters are the only tools I have to monitor my blood sugars, and I make treatment decisions based on their results. I need them to be consistent, and accurate. If I'm treating highs that aren't high, I could end up with a serious hypoglycemic event. And if I'm treating lows that aren't lows, I'll end up running higher and that, in the long run, will hurt my body.
What is my "true blood sugar?" Is it the result from the machine at the endocrinologist's office (which I believe is an old school One Touch)? Is it the lab result from a venous sample? Is it from any meter I can use at home? How can I trust any glucose meter fully, knowing these variabilities exist and are FDA accepted? What can I (we?) do to tighten these results?
How can I feel safe?
[Disclosure: I have a relationship with Dexcom. And Animas. But my relationship with diabetes takes precedence over any business relationship. So while my bias is exposed, I need to also say that my bias is highest when it comes to making sure I'm healthy.]