I'm sure everyone out there who is using a CGM or CGMS, I'm not sure which is correct, I usually just say CGM but anyways this is just a perfect example of when you should never rely on what your DexCom or ANY continuous glucose monitoring system shows. It is meant to show trends and does an EXCELLENT job at doing just that.
I thought I was feeling alright but felt just a little sleepy so I remembered that before I started using my Dex I always checked whenever I felt a little unusual including feeling a little sleepy in the middle of the day just like I was at this very moment. So I pulled out my OmniPod PDM to check and WOW!!! I'd better get something to eat!
I just thought I should share this for anyone who is thinking of starting or is questioning their own DexCom. I LOVE mine and use it every day watching my trends and learning even better ways to control my sugars. After nearly 30 years as a T1 I am by no means an expert although I feel as I'm sure many of you out there do that sometimes I know more than my Endo does.
Just wanted to share. LOVING MY DEX!!!!
I always go with what my body is telling me and test if I feel off from what the CGM is telling me. The CGM is an awesome tool for exactly what you said - trends.
I've been getting the same sort of results with my Dex. It has gotten to the point where I just can't rely on it. If the alarm goes off, chances are pretty good that I won't trust that it is worth checking. But my CDE says that people say the exact same thing about other CGMs, so switching would probably be pretty pointless. So now the plan is to put it in once a month to get a feel for what my post-prandials are doing.
The CGM is all about showing trends. I don't think it should never be used as a meter. That slow decline from 200 that you see in the picture was a sharp spike coming from 350 a couple of weeks ago. My CGM helped me figure out what I was doing wrong and correct it.
Thank you DexCom Seven+
I've heard great things about the Dexcom, but your advice is well-taken. I'd suspect, in this situation, you had a bad calibration and the Dex reflected values about 40 points higher than you actually were... so at the left side of the graph, you might have been more like 170 than 210.
For me, this was one of the reasons I just didn't find much value in CGMs. I've tried 'em and, for me, they just weren't worth it. I test upwards of 14 times per day and find that keeps me honest and on track. When I had the CGM, it was just too tempting to glance at the receiver and bolus or correct based on whatever number I saw. I know, I know...that's NOT how a CGM is supposed to be used. In addition, I was really worried about developing scar tissue. I'm very insulin sensitive so, for me, a pump is basically a necessity. The thought of doing something that would render pumping impossible was too stressful. And then there was the cost.
That all said, I know many folks LOVE their CGMs, and I am sure there are people for whom CGMs are invaluable. I don't have a huge issue with hypo unawareness or low BG seizures. If I did, I'd probably still be using a CGM.
Different folks need different tools for managing their D.
This is good advice. DexCom is a fabulous tool. I've found there are nuances to using it that are learned over time. It's absolutely fabulous for trending. I've made the mistake of acting on the sensor results without confirming with a fingerstick far too often. Sometimes I just think the sensor is spot on, but it usually backfires. I hear people get a great life out of the sensors, but Caleb almost never goes beyond a week. Some people find accuracy gets better after a restart, but I get suspicious. Your pictures speaks a thousand words. Sometimes I find it's just on a lag, and that it would have gotten to that 45 you show on the PDM in about 10 of 15 minutes. But sometimes it's off and those 47 points are really quite meaningful!
After 24 hours of watching my Dexcom Seven Plus and checking to confirm it's readings and realizing that YES this is day 12 for this sensor, I've realized that it's just the sensor. I usually do get fairly accurate readings from my CGM but this is the longest I've ever worn a sensor. It's been a busy week and I'd lost track. I'll change it tonight and I'm sure those numbers will go right back to their usual accurateness.
The trend data that I get from my CGM is great. It has helped me so much and I don't think I could ever give it up. I NEVER rely on it though. My body and the way I feel is the best tool that I have for detecting hypos.
I was warned by my endo, as well as people on this site in the Dexcom group (and I think even in the Dexcom manual) that Dexcom readings will be about 15 minutes behind a finger-stick reading, because CGMs measure your blood sugar via interstitial fluid as opposed to a blood sample. So, the fact that your meter read 45 when your dex read 92 is not surprising. Especially when you consider that meters can have a +/- 20% accuracy to begin with. I have had an occasional sensor that just seemed totally out of whack and never calibrated, and that can be very frustrating, since they're so expensive. What I've done to help prevent bad lows, is set my low warning on my Dexcom at around 70 or 80. When it alarms at 70 or 80 and my trending arrow is going down, I know that I'm probably lower that 70 or 80, given the time lag. Setting the low alarm at a higher number than I would normally treat, helps me catch lows before they get really bad.
I would definitely give up pump before Dex. I truly mean that despite the varying accuracy from sensor to sensor and from day to day with same sensor. Sometimes it reads within a point of fingerstick and then other times it is 20-30 points off. Under 20 points is very common. 40 points or more usually means it's time for a new sensor.
In the Old days we were able to spot 'Trends" the old fashion way.. Keeping a Written Log Book, noting Our Hypo's
-Then Came the Test Meter and we're supposed to Test even if we are hypo to record it, so when We down load them, it shows and thus a Trend if forming..
-If the CGM can do the same thing" And you can Afford it or have Insurance to cover it? Go for it!
I think we need all the Tools we can get to fight this Damn Disease
-Is anyone using Apidra for CB's? ( Correction Bolusing) Goes to work faster than NLog and gets those High BG's Down.. Faster.. Otherwise? It can take several Hours to get them down using NLog..
I was just thinking the same thing the other day. I would give up the pump way before the Dexcom. Dexcom is awesome (After the first day of calibration).