Is the Livongo Blood Sugar Meter Accurate?

It occurred to me the other day that even though I wrote a couple of blog posts and even made a video about it, I still haven’t addressed one major component of my new Livongo blood sugar meter: its accuracy.

How does it stack up to my Verio meter? More importantly, do I think it’s accurate?

Well…the answer isn’t cut-and-dry because I think it can be accurate…as long as my blood sugar isn’t above 200.

How did I arrive at this conclusion?

I conducted a little experiment.

Bear in mind here, I’m no expert in experimental design, so I established a simple setup for this. During the period of approximately two weeks, whenever I checked my blood sugar, I used the same drop of blood on test strips for two different meters: my Livongo and my Verio.

And the results were interesting, to say the least.

Whenever I was about 80-180, my results from the Livongo meter and the Verio meter were within about 10 points from one another. One instance, I was 86 on the Livongo and 92 on the Verio. Another time, I was 105 on the Verio and 113 on the Livongo. The meters never reported the exact same number at any point during my experiment, but I was happy whenever they showed similar results.

Things got dicey, though, any time I entered the hyperglycemic range.

Add a heading (1)
That 163 and 165 show how at times, the two meters were in agreement with one another…but then there’s that 231 and 262. Those are just a little too different for my liking.

It was weird and I can’t explain it, but the Livongo would report that I was anywhere from 20-50 points higher than what was on my Verio at a given point in time when my levels were 200+. This really surprised me, because I’d suspected that my Verio skewed a little higher compared to most other meters, so I never thought that the Livongo would prove me wrong about that. At times, it was truly maddening: On one occasion, the Livongo said I was 251 and my Verio said I was 204. That’s the difference of at least 1-2 units of insulin for me in order to correct that high! Even more frustratingly, because I didn’t trust the result from either machine, I checked my blood sugar again immediately and the Verio said 242, while the Livongo said 228.

WTF?!

That particular example was extremely confusing because I didn’t know which piece of technology to trust. And that’s the big thing for me: I need to know that I can depend on whichever blood sugar meter I’m using to deliver accurate results.

So again, remember that I’m no good with numbers, and that this is simply an estimation…but if I had to guess how many times the Livongo agreed with the Verio, I’d say it was no more than 7 out of 10 times. And I’m super bummed about that, because I’d genuinely hoped that I could trust my Livongo meter and use it full-time whenever I was taking a break from my CGM. Given the fact that it seems to be accurate when my blood sugar is in range, though, I suppose I could use that as motivation to work harder to prevent hyperglycemic readings…but I’m not perfect and I know that they will still happen from time to time. And I deserve a piece of technology that will accurately report them to me so I can make the best possible treatment decisions.

In theory, I still like the Livongo: It has a great design and some of its features (e.g., test strip reordering) are totally unique. But in practice? It leaves a bit to be desired.

The Expired Test Strip Experiment

Nearly every diabetes supply I own comes with an expiration date. Insulin vials, pods, ketones testing strips, and Dexcom sensor/transmitters are among the items that I’m always closely monitoring to ensure they’re still fresh and usable, but test strips? They’re basically the last thing that I worry about.

So I was curious when I recently noticed that my current test strip vial has an expiration date of 12/31/19. Would these strips still measure my blood sugar accurately, or was the New Year’s Eve expiration hard and fast?

I wanted to find out.

The Expired Test Strip Experiment
An introductory blog post to a potentially ongoing experiment.

My experiment design was rudimentary: I’d simply continue to use the 12/31/19 test strips until the vial was empty. I’d check any blood sugar results that I was unsure about against my Dexcom readings, and in cases that I deemed necessary, I’d use test strips with a far-off expiration (July 2020) to see how they matched up with the expired strips.

To my slight surprise, though it’s only been about a week since the old strips expired, it doesn’t seem to affect things much at all. They’re just as accurate as newer strips and my Dexcom.

In fact, in many cases, the old strips were only off (according to my measurements) by no more than 9 points. Not bad. I’ve had a wider spread in results between strips from the exact same vial, so the fact that the old strips were so close to new ones was interesting to me. And four days after the strips expired, I checked my blood sugar (I was 263) and used a new strip to double check that (it read 262). A single point difference is pretty impressive.

So now I know that I’m safe if I use test strips a week after they’ve expired…which is great! But now I’m sort of curious to see just how far out from the expiration date I can use them. I might hang onto this vial of test strips for a few more weeks and continue to test them against newer test strips. I might not (because really, when it comes to diabetes, there are just more important things to be worried about…and I might not want to push my luck and end up wasting strips). We’ll see what I end up doing.

I think that the more compelling questions to stem from this experiment are 1) how many other diabetes supplies are safe (up to a certain limit) to use after expiring and 2) why are supplies labeled with expiration dates if, in the grand scheme of things, they seem to function just fine after expiring? Could it just be a nasty trick played on people with diabetes by prescription drug companies…?

Those are the kinds of questions that really make me wonder.

Do Dexcom G6 Readings Become Less Accurate as Transmitters Age?

In my unofficial opinion: Yes, Dexcom G6 transmitters lose accuracy as they approach their expiration dates. And I’m not quite sure if I’m the only one who has noticed this, or if others have also experienced this frustrating phenomenon.

Let us help you find your center www.reallygreatsite.com.png
In my unprofessional opinion, yes!

I’m writing this after dealing with a dying transmitter that was showing its signs of decay by 1) losing connectivity with my receiver and 2) reporting inaccurate blood sugar readings. I’ve definitely narrowed the problem down to my aging transmitter, which (allegedly) had one session left before it was set to expire – everything else about this particular sensor session was standard procedure. And guess what else, everything about the entire 10-day session was obnoxious, because it was rare for me to have a single day with both accurate and consistent readings. Ugh!!!

I don’t know what’s more irritating – the signal loss or the inaccuracies. Actually, I DO know what irritates me more than anything else, and that’s the fact that the transmitters don’t seem to last for as long as they’re advertised. It’s just ludicrous, especially when you take into account how much these devices cost.

Many people with diabetes rely on this, and other forms of technology, to effectively manage diabetes. And when the technology can’t be relied on to do its job, we can’t perform our jobs as well. Diabetes is draining enough – is it too much to ask for technology to be trustworthy?

Testing for Accuracy, in Addition to Blood Glucose

This post originally appeared on Hugging the Cactus on March 21, 2018. I’m republishing it now because of a recent experience I had with my meter reporting inaccurate and inconsistent blood sugar levels. Has this ever happened to you? Drop a comment and let me know.

Blood glucose meters serve the sole purpose of checking current levels of glucose in the blood. Pretty self-explanatory, right? And it’s equally obvious that it’s crucial for all meters to generate accurate results so PWD can make the right treatment decisions based on those numbers.

Unfortunately, though, accuracy isn’t always what I get.

The other day, I was running low before bedtime. I corrected with an organic rice crispy treat (honestly, it was a million times better than the brand name kind). I waited nearly an hour for my blood sugar to come up. When my CGM wasn’t showing any progress, I tested: I was 47. It’s rare for me to be that low, so I tested again. 52. I believed it, especially since I was experiencing several hypoglycemic symptoms.

B. J. Palmer

I chugged a glass of orange juice and plopped down on the couch to wait for signs of improvement. Before long, I was freezing cold – a sure sign I was coming up, because I had been sweating 20 minutes prior. But I didn’t feel comfortable going to bed yet. I wanted to see if my CGM would show an up arrow. When it finally did, I made my way upstairs to brush my teeth and wash my face. In the middle of my routine, though, I decided to glance at my CGM again – and saw the dreaded ??? screen.

I decided then that the Dexcom should be out of commission, a.k.a. not trusted at all, for the remainder of the evening.

I ripped it out and inserted a fresh one, not really caring that it would wake me up in two hours to be calibrated. I would need to set at least two alarms for the middle of the night, anyways, if I decided to go to bed disconnected from my Dex. So it just made sense.

Once that was done, I tested again. I was pretty tired at this point and really didn’t want to have to eat something else, so I did it as quickly as I could. In my haste, I jostled my meter just so – enough that I saw the test strip, already marked with my blood, move slightly as it brushed against my PDM and was placed next to it.

113 mg/dL flashed upon the screen. Normally, I’d be thrilled! But I furrowed my brow. Something just felt…off about that reading. So I tested again.

206.

What?!

I tested a third time – 203. Okay, something was definitely wrong. Either that 113 was wrong (likely) or my meter had just produced two wildly inaccurate blood sugars in a row (less likely).

This is one of the many times that it’s convenient to live with another PWD. I asked my mom if I could borrow her test kit and see what result it generated. Seconds later…a twin 203 popped up on the screen, reassuring me that the 113 was a fluke on my meter.

Relief with the reality and irritation with the technology washed over me simultaneously as I went to correct the high with a bolus. I was glad I wasn’t heading down again, but irked that my meter had failed me. True, it was a bit of human error there, but aren’t we at a point in technological advancements where this sort of thing just shouldn’t happen? I put my life into the “hands” of my meter, Dexcom, and OmniPod. They should produce results that are undoubtedly accurate.

I guess we aren’t quite there yet.