The answer to the question on everyone’s lips: did he or didn’t he?

So on day twelve of my seven day monotherapy trial the Dexcom sensor started acting a little whacky. Not that I’m complaining, it had exceeded its useful life by seventy one percent. Not too shabby.

Failure came in the form of a progressive number of false low alarms as the sensor spooled down. I put in a fresh Med-T sensor and wore both systems together for another thirty hours or so. During the rocky start up phase of the Medtronic sensor, the ailing Dex actually did a better job for a time, then it petered out completely and I was back to just my old girl.

Looking ahead more than a week ago, I had wondered how quickly I’d fall back into my accustomed comfort zone. Would I be glad to be rid of the Dex; or would I miss it? Would I switch or not?

As you might imagine, this was no easy call to make. Let’s review. The Dex is a better sensor. Period. Unless you are a Tylenol addict (acetaminophen apparently can effect sensor accuracy). It is much closer, most of the time, to my Presto fingersticks. It also gets to the scene of the crash, literally, faster than the Guardian. And Dex is quicker to report on excursions. Don’t get me wrong, the Med-T sensor is very good. The Dex is just better. At least in my body.

This point was driven home to me very vividly when I was “back” on the Guardian. You shouldn’t, but you could dose insulin based on Dex readings. That wouldn’t really be safe with the Guardian. I had gotten used to fingersticks and Dex readings being neck n’ neck. When I went back on the Guardian it was a bit of a slap in the face every time I compared fingersticks to the read-out on the monitor. Before Dex I was just happy to have a reading in the same general ball park, and the good trend data. Am I going up or down? Is my blood sugar changing slowly, quickly, or terrifyingly fast?

But now, having lived with something better, going from Dex back to Guardian is proving to be sort of like trading-in a car with cruise control and power windows for a car that has neither. Yeah, you can live with it, but…

But I should point out that my current car, SweetRide, has neither cruise control or power windows. It is also missing the turbo charger, 5-CD changer, moon roof, power mirrors and remote locks that my previous Mean Green Machine had. So it is possible to adjust and be happy.

But back to CGMs, it is crucial to remember that the sensor doesn’t exist in a vacuum. It is only one part of an overall system.

In my book (figuratively), here is how the two systems stack up to each other. First, I prefer the Med-T transmitter. I’ve been wearing the same re-chargeable one since it was introduced, I think about two years, maybe a little more. The Dex is one of those sealed we’ll-guarantee-it-for-a-year-then-you-are-screwed models. I think a replacement runs a couple hundred bucks give or take.

And speaking of re-charging, the Guardian monitor takes AAA batteries. Easy to get and cheap. Small to carry spares. The Dex recharges “like a phone” according to my Dex rep. You know what? My damn phone is always running out of juice when I need it most. He points out that rechargeable devices are more environmentally friendly. Like I care. Most of us T-1s have our own personal landfills for all the trash we generate anyway.

I was particularly irked that the Dex monitor’s charge wouldn’t even last the seven days of the seven day sensor. All of that said, in practice, it really hasn’t been all that bad. The battery life indicator gives you plenty of advanced warning. I kicked around giving the monitor a daily ten minute charge when I’m in the shower, but was unsure how that would affect the life of the rechargeable battery. In the end, I waited until it was low, then plugged it in at bedtime and threw the tethered monitor into bed with me overnight. Seemed to work fine.

So speaking of the monitor, the Dex is big and ugly. But it does have a big screen, which turns out to be not so ugly. In fact, I got quite fond of it. It is very easy to read. One thing I didn’t like was I couldn’t “scroll” back through the display to check out past readings, which you can do with the Med-T device. The range of features and options are much wider with the Med-T device. For instance, you can find out the strength of the signal coming off of the sensor. You can see when your next calibration is due. You can set your rise and fall rate alarms to whatever you want instead of choosing between two factory defaults. Guardian also lets you have different threshold alarms for different times of the day.

And of course, one of the glaring deficiencies of the Dex is that, unlike both Guardian and Navigator, the Dexcom does NOT have predicative alarms. WTF??

But on the very much plus side is the Dex’s aggressive nature of alerting you to alarms, long my biggest beef with the Guardian. Dex has a teeth-rattling vibration and a slap-you-across-the-face audio alarm that can actually wake you up.

Also in the mix is the superior range of the Dex. And by range I mean the distance between your body with the sensor inserted, and the monitor. With Guardian, you’d better not let the monitor get separated from your body. In fact, you literally need to wear it on the same side of your body that the sensor is in. Yeah, it is technically wireless, but in reality you just have an invisible infusion set hose connecting you to your sensor.

Dex seems much more robust in this sense, but not enough to communicate from your night stand through a pile of winter blankets and comforters. Just as well, the hyperactive vibration would probably cause it to migrate right off of the night stand and on the to the floor, likely hitting a cat on the head at the end of its fall.

Now it is only fair to point out that if the Guardian sensor and monitor get separated, the sensor will store data until it communicates with the mother ship again. This is a great feature unless you happen to experience a low blood sugar during the separation period.

Another big difference between the systems is sensor size. This is one area of human endeavor where bigger is definitely not better. The Dex sensor, the wire that ruptures your epidermis and stays parked in your interstitial fluid for the better part of a week or more, is a fraction of the size of the Guardian. Well, that may be an exaggeration, but it is very much significantly smaller.

On top of that, the method of insertion is quite a bit different. The Med-T Guardian has such a bad insertion device that on more than one occasion people who work for Med-T have apologized to me for it. It is so bad I’ve kicked it to the curb and just stick them in by hand, a process that is frequently painful. I had written the pain off as one of the many costs of staying alive with diabetes, and just dealt with it.

Before inserting a Med-T sensor, I’ll often mentally chant the refrain about fear from Frank Herbert’s epic sci-fi novel Dune:

I must not fear. Fear is the mind-killer. Fear is the little-death that brings total obliteration. I will face my fear. I will permit it to pass over me and through me. And when it has gone past I will turn the inner eye to see its path. Where the fear has gone there will be nothing. Only I will remain.

Yeah, it sometimes hurt. Once I bleed so much I stained Debbie’s Berber carpet. But I viewed it as the cost of healthy diabetes. I once told one of my Guardian-enabled T-1 patients, who is more a wuss than I am if you can believe that, to just buck up and be man.

That said, I’m no glutton for pain and Dex sensors don’t hurt on insertion. With the inserter you could even get creative about breaking new ground on your body, sensor location wise. If you are traveling, the Med-T sensors are quite a bit more portable. The Dex sensor, with its elegantly designed one-shot inserter is on the large size.

And speaking of traveling, originally, Med-T sensors needed to be kept cold. They were even shipped Red Label UPS in styrofoam sarcophagus with ice packs to survive the trip from Northridge where they were made, to wherever their D-folk users were located.

One of my early road trips, ending in a hotel room with no mini-fridge, was a nightmare of bucks of ice. Nowadays, neither sensor needs to be kept cold.

As to software, one of the best out there is the doctor office version of CareLink (not the consumer one you can use online). Oddly, however, it is not compatible with the Guardian, which is Med-Ts flagship stand-alone CGM device. Double oddly is the fact the Guardian pre-dates CareLink Pro by quite a bit. Guardian users are relegated to downloading their data to the limited functionality web-based CareLink where all they get is a hand full of PDFs.

The Dex software has come a long way from after-thought to top-of-the-line. I’m irritated that the display is a series of data points reflecting monitor readings rather than solid “trace lines.” While this is at least consistent with the style used in the monitor, I find it highly distracting when studying a large number of days at one time. The graphic resembles a collision between two trucks carrying decorated Christmas trees.

That said, the Dex software has some pretty sophisticated filtering options. Let’s assume you’ve been wearing it for three months. Want to just look at three months of Sundays? You can do that. Want to just look at hyperglycemia? You can do that. What to just look at… well, you get the idea.

The Med-T device, being built into the housing of a Med-T pump, has the full range of pump clips, cases, and holsters. Too bad Med-T didn’t use all that empty space inside the case where the insulin would go if it were a pump to install a louder alarm. The Dexcom has a case that is truly pathetic. Navigator has both a very clever belt holster and a i-Phone style silicone skin to choose from. I for one, would love to see this kind of skin for the Dex, as I had given up on the belt case and was just carrying it in my pocket anyway.

The Dex case is soooooo bad that third-party vendor Nutshell in New Zealand, of all places, has stepped in to sell cases for the device. (But they are expensive, “square,” and have no window for buttons or the screen. Probably just a PDA case some d-folk who works there realized was big enough for the monitor to squeeze into.) BTW, Gina a.k.a. Mommy of Three over at tudiabetes reports that the Verizon “Pouch with Swivel Clip and Wristlet” for the LG Chocolate line of phones also works great and runs less than three bucks per case.

While the Dex transmitter is about half the size of Med-Ts, the skin landscape required is more due to the size of the sensor frame and sticky-pad. The Med-T realistically has to be covered by an IV3000 bandage or the transmitter will “flap” and get pulled out. I, out of habit, covered the Dex an IV3000. Well, two IV3000s, as one was not big enough and I had to overlap them. Based on the sensor tape’s resistance to being removed, even after 13 days, it probably wasn’t necessary.

In several nutshells. Those are the differences. I had a choice to make. Was it clear? No.

So… let’s see… should I make you all suffer by waiting until next time to tell you what I decided?

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Nah. That would be cruel. I did it.

I switched.

The tipping points for me were the combination of the sensor accuracy and the louder alarm. For me those two things out-weighed all else. For me, sensor accuracy and noisy alarms are the essence of Continuous Glucose Monitoring. In the end the choice was simple because there simply was no choice. No array of features can outweigh accuracy and noise together. Had the Guardian been louder I would have stuck with her. The rest of the feature set were strong enough, that had her alarms been loud, she would have even outweighed the Dex’s superior accuracy.

After a minor squabble with my insurance company, this morning got a call from Edgepark, my DME supplier. I’m approved for Dexcom. Would I like FedEx to ship my new CGM and three month’s worth of sensors to my home or work address?

If there weren’t a blizzard outside right now I’d be sitting on my porch, smoking a pipe, and watching for a white truck.