Calibration design problem?

My son Santi is 3 yrs old, dx at 18 months. We used shots for only a month after his diagnosis, and then started pumping with OMNIPOD. After 6 months or so on the OMNIPOD, and with the help of our ENDO, our insurance company finally approved DEXCOM in a monthly basis. At the end of this month, we need to ask for approval again.

Our experience with the DEX has been little dissapointing. We find that meter readings vary more from 60 to150pts off the METER readings at least 60% of the time-- either low or high-- . We have followed the recommendations made by DEXCOM customer service, CDE & Doctors as far as site placement & insertion procedures and tips for this forum.

We have come to the conclusion that the only reading worth noting to take corrections for highs or treating lows are the ARROWS or trends shown by DEX. Also, during sick time is very useful as it allows us to anticipate the effects of the medicine and react promptly.

I read another discussion here where some of you have had this calibration issue. I thought the DEXCOM could work better as my son ages. Any input, ideas, or recommendations are very welcomed. MERRY XMAS!

Has anyone compared DEX with NAVIGATOR?

My experience with DEX has been great…especially the trending, if not for this device would have never finished half ironman, because pump site fell apart after swim…but the Dex helped me regulate with mixed in shots and so much exercise…even when i got out of the swim my Dex was dead on…i feel it is like this approx 85% of the time, knowing that my BS meter has a +/- 20% accuracy…how can you blame the Dex, when the numbers you are feeding into it are not accurate…but the trend for the Dex is the best

Have you read thru some of the calibration tips on this group? I did find that when I read thru the tips here, it really helped the accuracy of my readings, especially the one about making sure my BS was stable for 15 minutes before putting a calibration in.

The other comment would be to ask about the accuracy of your meter. I realized that I needed to get a new meter after I saw that I would do two fingersticks and was getting big differences in the readings. If you are putting calibrations in that are far off, that will have an impact on the quality of your readings.

As far as the Navigator and Dexcom go, I got my Dexcom when my Navigator died and Abbott was not able to replace it. Mine died in January and I had to wait until April to get a refund from Abbott. The Navigator is still not back on the market yet. As people’s Navigators die, they are being offered buyouts or they have to wait until the new one comes back on the market. Abbott originally thought that would happen this month but it did not. Even if you wanted to try the Navigator, you would not be able to get it. After what happened to me, I would be very leery about a company that did what they did. Unfortunately, this year’s backorder problem was the 3rd time that I know of with Navigator backorder problems but it was the longest that ever happened.

I like the Dexcom better than the Navigator. They were both good with in range readings. Dexcom is better with lows than the Navigator was for me. Both were more off with highs but my problem is more with lows than highs so that does not matter to me. I like the alarms on the Dexcom better. With the Dexcom, you can set the length of the reminder alarms. The Navigator beeped at you every 15 minutes until you were back in range. That is fine with a low but when it takes my insulin 20 minutes to kick in, I don’t need reminded every 15 minutes for a high. The Navigator’s predictive highs and lows are based on the numbers you have your high & low settings at. The Dexcom is the rapid rise & fall and will alert you regardless of what your BS is or what you have your alarms set at. I feel I get better warning of lows that way. A lot of parents like the Navigator better because it has a greater distance and they are able to keep the receiver with them and know what their kids BS is doing as opposed to the kid having the receiver on their body.

Here is an article I wrote on my blog comparing the Navigator with the Dexcom. Some of this stuff will change if Abbott is ever able to release the new version of the Navigator.

Thanks JM, it’s inspiring to know how the DEX has helped you through your lifestyle. I want my sons to be able to compete as well, so I’ll use all means necessary not to allow the diabetes limit my son’s pursuits, thanks.

Thank you so much for the tips. Yes, I have read some of them--can't say all--, but I'm going to test the meter as you have suggested-- thanks for pointing that out.

I didn't know about Navigator's company history. Thanks for sharing that too.

There is also a Navigator group here at TuDiabetes - it has been fairly dead for awhile because I don’t think very many people are left using the Navigator but it might help in your decision if you can read some of that stuff.

I’m not sure if this is a helpful comment but I believe that our body chemistry sometimes doesn’t work with certain sensors. When I trialed the medtronic sensor it didn’t even trend in the right direction for me and was never closer than 43 points off my meter. I trialed the Dexcom less than a month later using the exact same methods and it was spot on the whole time (I rarely see a Dex reading more than 15 points off the meter). I think my body chemistry just killed the medtronic sensor’s readings. It’s possible if you’ve tried everything that perhaps the Dexcom has the same reaction to your son’s body chemistry. I hope you find something that works because a working CGM has made all the difference in my treatment~!

I too have to agree with Rebecca. I began pumping with the Medtronic 722 because it was the only pump combined with the CGMS. I believe I developed more gray hair from trying to deal with the CGMS than with the pump, and as time went on, the MM CGMS became more frustrating to where I turned off alerts at night (when needed most), and finally quit using it. It was hard to calibrate, inaccurate, and a pain. So I resisted spending the money and getting insurance approval for the Dexcom, but I have to say it is pretty close to right on for me and I am loving every minute of using the Dex. I am still learning what works best for me, such as inserting a new sensor at night but not starting it until the morning, not fully trusting the readings for about the first day and a half to two, and realizing that it does have trouble with rapid blood sugar changes. But I am successfully getting 2 full weeks with good readings from it since I began. Plus the insertion of the Dex is virtually pain free (most of the time!) when compared to the Medtronic. I do hope you are able to find a good solution. While there is no perfect CGMS, it is so helpful especially with catching the swings in our blood sugars and hopefully allowing a quicker response to maintaining a more stable blood sugar level.

Thanks for sharing your experience. I'm going to try start the sensor at night, maybe that helps. Last night, I got ERR#1 message after calibrating the DEX for a wrong value of 401 when Meter read 116.... This is in Day #5 of this DEX. I'm following the recommendations in the manual of trying to enter on more BG after 1 hour to see if it re-calibrates??

I wonder if it's got something to do with lack of fatty tissue in my 3 yr old around the abdomen?

It is ironic that you mention the calibration being off, but the arrows helpful.

For the last 3 days my arrow keeps disapearing for a couple of hours and then come back again.

All this while the calibrations have been pretty accurate. But no Arrow.

I also keep getting alarms while there is no message, no low, high, or fast move. I can not figure out what the alarm is for.

But every time I check with my meter, it is pretty accurate.

There have been times when the Dexter was 50-100 points off but that usually was during the first day or two of use of a sensor. Eventually it seemed to settle down. Lately I haven’t noticed that problem … perhaps they had a bad lot or two. Overall, I am very happy with the product, especially during the second week of use.

Hey Isaac, thanks for the post. I’ve read your other posts as well (flatliners & others), and they’ve been helpful.

I think the site’s condition is one cause for bad readings. I just tried the last two weeks placing the sensor in the love handle (eventhough my little one does not have much), and it’s been working better.

Yes Jeff, second week is much better. I started using a tip someone posted here to leave the sensor overnight without starting, and it’s helped as well. Our problem after 4 days or so is trying to keep it in place since baths & activity on my little one get it loosen.