Tag Archives: calibrations

My CGM Tips

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So, most of you know who have been reading my blog know that I am using a Minimed Revel pump + CGM for to control (or try to at least) my diabetes. Lately, I simply could not figure out what I was doing “wrong” with the cgm and why it wasn’t catching my lows or highs and things like that. I even posted a request on my DiabetesDaily blog asking for help from other Minimed CGM users as to what they do for more accurate readings. Well, after a week or so of buckling down to really try and figure this thing out, I have a few tips to share that may help you if you’re using the same CGM (or even a Dexcom – I’m not biased!). Of course, these are only tips that work for me. I am not saying you have to do these things, and as a matter of fact, I would rather you speak with your health care provider before trying these just to get the OK from them.

1. Undercover and overcover. (This one applies to the Minimed sensor – Dexcom users can’t do this one, sorry!)

After inserting a sensor, but before attaching the transmitter, put a piece of tape to cover the “sensor head” (the part that is purple-ish and flat), but under the “feet” of it. Take a piece of Tegaderm or IV3000, and cut it in half. Then, cut a slit in it that would look like your eyelid opening (just imagine this: () ). VEEERY carefully, slide the feet and connector end through the hole, so that part of it is under the feet and connector, but the other part is over and completely covering the sensor head, and secure it down.

Why do I do this? As an added layer of protection against water. I have found that if it gets wet and just a smidge of the sensor is above my skin, the sensor readings aren’t as accurate as they could be. Since I have done this, my readings have improved a lot!… but not as much as also doing this: (proceed to tip #2).

 

2. Don’t just let it get wet…. SOAK IT!

That’s right. Soak it. Overnight. If you put a reminder on your phone (or use the Medtronic app on your iPhone to remind you!) for the night before the sensor-change day. Insert a new sensor, secure it with the under/over cover method, and also with a total over-cover. Take another Tegaderm or IV3000 patch, cut a small square out of the paper that would be big enough to over the sensor, place it in the middle of the tape, then place the tape over the sensor. That way, you won’t accidently rip it out overnight or scratch it out (as I have done before). Then, the next morning, carefully remove the top layer of tape, and connect your transmitter, and add a final top layer of tegaderm to secure it and add that top layer of waterproofing. (Which, I have to say – the system is approved to be waterproof, but as I said before, I do it just for sensor accuracy for me.)

Sensor Change

Photo 1: Sensor under/over covered and covered for bedtime.

Photo 2: Carefully removed the top “sleeping protective” cover.

Photo 3: Connected the transmitter. Yey, green light!

The reason why I decided to do the soak it trick is because I noticed that my sensors (seeing as you only get 3 days out of these suckers) would be best  only on days 2 and 3. And, with me, extending the sensors just is not an option because I don’t get very good readings by day 5, so, I thought “hey, maybe let it soak and see what it does”. Well, by golly, it worked. And has worked ever since. (note: I also used to do this with my Dexcom, and it worked very well too!)

 

3. Log to calibrate.

I know it may be a hassle to do, but take one week to log everything – food, insulin doses (for food or corrections), exercise, etc, and find out your “quiet” times. The times when your blood sugar is going to be the most stable. Granted, yes, I know you Dexcom users are probably thinking, “Yeah, well, I don’t have to do this because I can calibrate at any time.”, and this is true, but trust me, it helps you guys too. Use these “quiet times” to calibrate your sensor. My times are (1) first thing in the morning, (2) mid-afternoon and (3) before bed. Your times may differ, just as your diabetes may differ from mine (to an extent). The reps will tell you to calibrate 4 times per day because though you’re required to every 12 hours (2x per day), 4 is the optimal amount of times, and more than that just gives it too much info. But for me, 3 times is a good number because it’s one more than 2, and one less than 4 – sort of the safe zone, so that it has enough information, but I have an extra “okay to calibrate” card up my sleeve as well for when it’s needed. And, if you are really, really, really a perfectionist about it (which, you’ll have to lose some of that perfectionalizm anyway to be any brand CGM user as they are NOT perfect), you can even set reminder alerts in your pump to go off at the times that are best for you to calibrate based on your awesome logging data.

 

So there you have it. I’m still working on other little quirks that may make it even better, but at this point, I’m pretty darn satisfied with the improvements I’ve had so far. And, if you have any tips you would like to share other than these, please – by all means, share them with me by leaving a comment. I would love some feedback from others who have some tricks up their sleeves too!

Dexcom Margins and Tips

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If you remember my last post about the Dexcom, I was quite irritated at it’s inaccuracies lately. I decided to call Dexcom once more to see if they could give me any information as to whether it was pregnancy-related or if I was just “special” and it didn’t like me.

I called and the nice lady at Dexcom support walked me through sending them a report from my Dexcom software to them for review and she would call me back. So, I did and within about 15 minutes, the phone rang and she went through a few things with me. She concluded this from her review:

(1) You’re calibrating too much.

Really? I didn’t know that was possible with a Dexcom. She said that I was calibrating even when it was reading within the 20% range, which when it’s done, throws off the sensor’s “sensing”. She said not to calibrate when it is within the 20% range and that it would even itself out. I have one issue with this. If I’m, just for kicks and giggles, 56 per my meter, and the Dex is showing me 78, I’m going to calibrate. Why? Because 5.6×2=11(ish), which means, the Dex shouldn’t be showing above 67 nor below 45, right? Right, so I calibrate. What I go obsessive about is when I calibrate and it still shows the 78. I want it right, so I wait about 5 minutes and recalibrate. She said that’s where the no-no is and I need to stop.

Ok, so, taking the same 20% principle, if I’m 164 per fingerstick, that means the Dex is allowed to show me a +/- difference of up to 32mg/dl, meaning it’s acceptable to be between 132 and 196? HA! Not in my book. And the higher the number, the more leeway they are allowed.

I’M NOT COMFORTABLE WITH THAT MUCH OF A MARGIN OF DIFFERENCE! I honestly don’t know one diabetic who is. I mean, My question is this…. If our meters are allowed a +/- 20% difference, and our Dexcoms are allowed a +/- 20% difference……

WHO’S TO SAY that our BG could actually be 126 BUT….

Our BG meter is showing a 101 which means we calibrate based on this 101 reading and our Dexcom takes it one step further allowing their 20% allowance, leaving us with a potential Dexcom reading of 77.

THAT’S A BIG DIFFERENCE!!!!

Okay, Yes, I know that’s a lot of math, and yes, I know it maybe a stretch to think this could be true, but IT COULD BE, and I’m not happy with it. I’m not happy with the fact that Dexcom is also allowed an additional 20%+/- leeway to our meter’s leeway.

So, yes, sometimes, I might be calibrating too much, but it’s because I want it to match my meter within a very close range (in numbers, not percentage).

The next thing she evaluated was that…

(2) You’re calibrating during out-of-range times.

To which I had to argue. I have used the Dexcom system long enough to know not to try to calibrate while there is an antenna symbol in the box where the BG reading should be. I told her this was also mentioned the last time I called in, but that I had not been calibrating while “out of range”. I told her that I always make sure there is a reading there before calibrating because otherwise I know that reading is disregarded in the system. She said what could  be happening (hold on to your hats with this one…) is that it’s due to the calibrations being between  the 5 minutes when the system “senses” the BG, so it may just be showing on their side that I’m calibrating during “out of range” times.  I said that to say this: MAKE SURE YOU’RE A-L-W-A-Y-S calibrating when there is a number in that upper right-hand corner box. Otherwise if you’re having a problem and you call in and you send in your report, they might see some of your calibrations as being done while out-of-range.

 

dex armAnyway, since calling in I have tried to keep my calibrations down to when it’s (1) asking me to or (2) outside of the 20% allowance. It has been pretty well on mark, except when it shows “LOW” and I’m not. Those are the ones that seem to throw the sensor for a loop and I have to calibrate (per the 15 minute rule) a couple of times to get it in line. I also had the Dexcom sensor in my tummy before which usually gives me very nice readings when compared to my meter, but I had to change it today and I am trying my arm (again) since I’m going to have to find new spots soon.

I know a lot of you have left comments that your Dexcoms have been off as well, so maybe try these tips she gave me before throwing in the towel (or throwing out the sensor). I hope they help!