Dexcom Dosing Sing This Song…


If you read this blog, you know that I have a son with Type 1 Diabetes, and he takes insulin, and has a CGM. It’s a Dexcom brand continuous glucose monitor, and I LOVE IT. Before he had it, I was afraid his blood sugar would drop drastically while he was in school, or he’d go low in the night and not wake up.

Now that he does have it, it’s great, but like any other piece of technology, it’s not perfect.

That’s okay, Dexcom, I love you just the way you are. BLOG flight2

Does the sensor go wonky when you just put it on, or when it’s near the end of its life? Yes! I know that when the little trend line looks like Woodstock’s flight path, it’s time for a change. Does it wake me in the middle of the night with false alarms? Yes! But, only once in a while, and I can live with it, and it also wakes me with real alarms – the reason we got it in the first place – which has kept my kid from the aforementioned scenarios more than once.

Early in my boy’s “journey”, we heard a speaker ask an audience of Type 1’s if they ever calculated their insulin dose from their CGM without testing (that is, using a drop of blood on a test strip to get a reading from a blood glucose meter). All of them raised their hands. They weren’t “supposed” to do this, it wasn’t FDA approved, but most of them were adults, and probably pretty comfortable with their diabetes. If they felt okay, and their CGM said they didn’t need a correction, they skipped the strip and dosed.

It seemed miraculous! No more finger pokes? Sign us up!

However, the question was NOT, “How many of you always dose from your CGM,” it was “Have you EVER.” They would test, of course, if there was any doubt – they would be putting themselves in danger if they didn’t. That is because everyone who has one knows they can be wrong sometimes.

Take lows, for example: a CGM will alert the user if their blood sugar goes below, say, 70mg/dL. (You set your own high/low thresholds.) Lows can be sneaky and they can mess with a person’s judgment, so generally when it goes off, they test (old school strip and meter style) and treat if the alarm is correct. (Treatment for LOW is eating or drinking sugar, btw.)

Since the CGM takes a while to catch up, it can look like the person is still low, even after 15-20 minutes. The protocol for low treatment is to test again 15 minutes after eating the sugar. But, if you’re just watching the CGM, the reading might go even lower after you treat. At that point, it’s wrong – inaccurate! – but you’re still not sure, so you might eat more glucose, shoot your blood sugar into the stratosphere, and then you have to treat for a HIGH (with insulin).

Once you get used to the CGM, you learn to be patient and wait for it to catch up. Like I said, not perfect, but much better than a meter alone.

Several months ago, the FDA did approve the Dexcom CGM for dosing. Hooray! Throw away those expensive test strips! Because we all know when the FDA approves something, it’s guaranteed safe.

After all, why would a group established for the safety of human beings, approve something if it weren’t safe or effective? To make a product like a CGM more attractive to consumers and healthcare providers, that’s why. The manufacturer was just so sick and tired of customers saying, “You mean I still have to test?” So they asked the FDA very nicely to please change that restriction. Type 1 Diabetics have grit and gumption! They can decide whether to test or not. If the CGM happens to be off that day, it’s the risk they take. (Which is great – I might be that way, too, but I’m making the decision for my kid!!)

I was devastated the day my son was diagnosed. I spent a whole day in the ER learning only a bit of what I would need to know, and I spoke to a dozen doctors and nurses. One of them was an endocrinology resident who told me, “If you’re going to get diabetes, now is the best time in history to get it.” Oddly enough, that didn’t make me feel any better, but I knew what he was trying (ham-handedly) to say:

Medicine and technology is available and amazing. Not affordable, but that’s another post… There’s more on the market and in the pipeline for anyone diagnosed with diabetes, which is still a crappy, unpredictable, life-long disease.

I love the CGM, and someday, I might love for my son to have an insulin pump, but realistically, they won’t take his diabetes away. There have been times I’ve dosed him from the CGM – usually if I’ve tested him recently for some other reason and I’m confident nothing drastic has happened. But, when that alarm goes off in the night, you better believe I’m pricking his finger, no matter what Dexcom or the FDA say. Trust but verify!!

As a parent, I didn’t need this FDA indication. They had me at “He’s low.”


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