In my recent post about a blogging vacation, I made a notation on my Dexcom tracing about static interfering with my CGM readings. This has actually been a significant problem for me this winter and deserves some explanation.

Most of us who use CGM’s and pumps have had frustrating phone calls with customer service reps who somehow blame a multitude of problems on the phases of the moon, user errors, and the ubiquitous static. This winter I had multiple Out of Range error messages with my Dexcom G4. My transmitter was out of warranty and was the first device replaced. The number of Out of Range and ??? alerts escalated and I had instances of not being able to enter calibration numbers. Dexcom has always been responsive to my calls and quickly replaced the receiver.

New transmitter. New receiver. Although the calibration errors were fixed, other problems persisted and I assumed that they were somehow related to my sensors. I use each sensor for 2-3 weeks and had been using the same lot number of sensors all winter. I know that the Dexcom manual indicates that Out of Range readings are related to communication between the transmitter and the receiver, not the sensors, but….

I called Dexcom and fortunately got a great technical support rep. We spoke a while and she started asking questions. What was I doing when the Out of Range problems happened? Walking the dog. Shopping at a Target. What was I wearing? Athletic clothes. Golf clothes. I don’t know because I didn’t think about it. Where was the sensor inserted? Mostly upper leg sites.

She indicated that she thought it might be a static problem. I wasn’t convinced but tried to stay open-minded. Because I had used the 7+ for several years and the G4 for over a year with virtually no Out of Range readings, it didn’t make sense to me that all of a sudden static was wrecking my CGM universe. I was surprised when at the end of our phone call, she indicated that she was sending me a new transmitter.

If you work for Dexcom, please quit reading now.

After the phone call, I immediately started wearing some of my cotton clothes. Magically I didn’t have any Out of Range problems. A few days later I wore my favorite synthetic fabric athletic pants. One dog walk later and I was Out of Range for several hours. I wore my golf shorts that are cotton, but have shiny polyester pockets and guess what. Out of Range problems.

After these episodes/experiments my last two Dex sites have been upper arms. No synthetic pockets full of pumps, CGM receivers, and glucose tabs electrifying my transmitter. No static. No Out of Range problems.

Arizona almost always has low humidity, but this year has been even drier than normal. Like most of the Southwest, rainfall has been almost nonexistent in 2014 and my area has only had measurable rainfall one time since January 1. For the most part my wardrobe hasn’t changed. I have worn the same two pair of REI hiking pants for almost ten years and never had problems with the 7+ or the G4 last year. My golf clothes and everyday capris are well-worn and experienced when it comes to diabetes. But the extra dryness this year must have thrown the G4 over the threshold of what the transmitter can tolerate. I have struggled with my skin this year more than in the past, so I think the G4 and I are both rebelling against the 2014 desert dryness.

Remember now if you work for Dexcom and didn’t quit reading before, please quit reading now.

I have not opened the new transmitter. The old transmitter has been working fine since I’ve been protecting it from static generated by mutant pockets of synthetic/electrifying and polyester/nylon materials. Should I feel guilty and call Dexcom to genuflect and confess my dual sins of synthetic fabrics and static electricity? Probably not. The new transmitter was sent to me with no conditions attached and I was not asked to return the old transmitter. I won’t abuse the possession of the new transmitter by selling it or giving it away. Like most people who use a CGM, I will sleep a bit better knowing that I have a back-up transmitter. Both times when I have begun using a new transmitter since starting the G4 in November 2012, I really didn’t think that there was anything wrong with the old transmitter. I never got a battery warning. I got things like ??? and calibration problems.  But if you have a new transmitter in your cupboard, they won’t talk to you about other problems unless you have started using the new transmitter. Both times the problems did not resolve until the receiver was replaced. So I think I prematurely sent two transmitters to medical trash before they truly bit the dust and I have never had the luxury of a back-up for even a few weeks.

I’m not trying to justify medical theft and if you work for Dexcom and are still reading (even though I warned you to stop!), you know where I live and can give me a call. Another somewhat moral issue I’ve been wondering about is whether I violate any trademark/copyright issues when I use images of medical devices in my graphics as I did today with the G4 transmitter. Because I am not profiting from my use of the image and it’s being used on a personal blog, I doubt that anyone is going to chase me down. Today I obscured the image big time with a sketch filter in Photoshop and don’t know whether that’s a good or bad thing. I will say that I really like today’s graphic and think it does a good job of illustrating the static issue.

I’m back in Minnesota now. Plenty of humidity with rain and snow. I’ll be curious to see how my Dex works this summer. I really like using leg sites in warm weather so that I don’t have a visible mess of the transmitter and dirty adhesive on the back of my arms when I wear short-sleeved shirts. I’ve given up sleeveless shirts forever. 60+ years of sun exposure and diabetes-related skin problems have motivated me to look for long-sleeved shirts that can be worn in warm weather. That will be a blogpost someday soon, but I’m still working with my dermatologist to figure out exactly what is going on and what, if anything, we can do about it.