Cgm, wtf?

Sitting here checking out other people’s blog posts on TuDiabetes, when I heard the distant, but unmistakable, sound of Eric’s CGM alert. So off I went, faster than a speeding bullet, to find that his CGM was signaling a low. Not a drastic one, mind you – CGM was recording 89, and his BG had been running at least 10 points higher than the CGM most of the day. He’d been at 126 on the meter (113 on the CGM) at bedtime so I was a little surprised by this – standard for 2 hours post bedtime is an alert for high BG, not low. But, whatever… grabbed the meter, found a finger in the darkness, turned on the night light, poked/prodded… and the result was a BG of 247. Wha…? THAT I did not expect. He’d had a bath before bedtime so it wasn’t likely there was food still on his fingers, but just in case, I swabbed with an alcohol wipe and stuck him again (he slept through both sticks, bless his little heart). This time the reading was 246. Clearly, the CGM was WAY off calibration, so I entered the second reading into the sensor, checked to see if he needed a correction (he didn’t, at least not according to the insulin on board report on his pump). And… my next step is going to be to check him for ketones, because it just occurred to me that maybe this high is a sign that his site needs to be changed – that happens after a day of vigorous activity (horseback riding) and is especially likely after bathtime. But what is up with the CGM, getting that far out of sync in just under 2 hours? At 8:30 when I took his BG before tucking him in, he was only 13 points apart from the meter. So then over the hour he shoots up but the sensor says he’s gone down? That’s wacky… any ideas, anyone?

A faulty machine! I would get on to the manufacturers and see what they have to say! I do not confess to know anything about pumps etc, but I think that something is seriously wrong with the machine and may need replacing!

I struggled with the CGM for more than a month with full support from my trainer and Medtronic tech support and they had no real explanation for its lack of proper functionality with me. I’m happy with the finger sticks because I can rely on them.

Follow up – I found the main cause of the issue, and the machine isn’t faulty. What’s faulty are the instructions that come with it. They say let it “wet” for 5 to 10 minutes, and that’s what I was dutifully doing. Upon consultation with the Medtronic trainer, her recommendations was more like 10 to 15 minutes. When I started doing that, I found a lot more consistency in the calibration. I do still get some wacky results, though… but generally when it’s been off the charger for more than a week at a time, so my other step has been to make a point of putting it on the charger each time I change the sensor so that it’s always fully charged.