# Dexcom: 138 Fingerstick: 305 **URL:** \ **Category:** C/GM\ **Created:** [May 17, 2017, 3:32am UTC](https://forum.fudiabetes.org/t/dexcom-138-fingerstick-305/954 "2017-05-17T03:32:40Z")\ **Posts on this page:** 16\ **Page:** 2
**Author:** ![TiaG](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/tiag/32/594_2.png) [@TiaG](https://forum.fudiabetes.org/u/TiaG)\ **Post date:** [June 14, 2017, 7:46pm UTC](https://forum.fudiabetes.org/t/dexcom-138-fingerstick-305/954/21 "2017-06-14T19:46:33Z")
So this happened once again: Sensor was reading 117, then droped -67 points, then for the last 15 minutes has just been in LOW territory. Finger stick? 132. The sensor overall has been really accurate and whenever we calibrate it’s right on. I’m wondering if there’s a specific physical cause that can be pinpointed for these weird anomalies. It’s basically like the Dexcom has a psychotic break, then quickly recovers for a while. Does this have to do with hitting a muscle or something getting bent inside his arm or something? ---
**Author:** ![Michel](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/michel/32/387_2.png) [@Michel](https://forum.fudiabetes.org/u/Michel)\ **Post date:** [June 14, 2017, 7:56pm UTC](https://forum.fudiabetes.org/t/dexcom-138-fingerstick-305/954/22 "2017-06-14T19:56:58Z")
@TiaG, did you have any sudden sensor drop in the process? Either losing the sensor or a sudden sharp drop, say 30-40 over 10-20 minutes? How sudden was the -67 drop? Either of these would mean that the sensor fiber somehow moved. [EDIT] Typically it is a pressure drop, if he somehow put pressure on the sensor or hit it. ---
**Author:** ![TiaG](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/tiag/32/594_2.png) [@TiaG](https://forum.fudiabetes.org/u/TiaG)\ **Post date:** [June 14, 2017, 8:09pm UTC](https://forum.fudiabetes.org/t/dexcom-138-fingerstick-305/954/23 "2017-06-14T20:09:30Z")
well it went down -67 in just ONE reading. Then for the next four or five readings stayed in the -53 to LOW range. And then I tested, he was 132, and yet Dexcom only went up to 82 (I didn’t calibrate with that reading). So it could be a pressure issue except that he moves around so much it’s unlikely. He’s at daycare and this is all being reported remotely. ---
**Author:** ![Chris](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/chris/32/382_2.png) [@Chris](https://forum.fudiabetes.org/u/Chris)\ **Post date:** [June 14, 2017, 8:17pm UTC](https://forum.fudiabetes.org/t/dexcom-138-fingerstick-305/954/24 "2017-06-14T20:17:23Z")
Where is this sensor located? We have seen variability in our abdomen and thigh placements. Arms work best for us. ---
**Author:** ![TiaG](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/tiag/32/594_2.png) [@TiaG](https://forum.fudiabetes.org/u/TiaG)\ **Post date:** [June 14, 2017, 8:17pm UTC](https://forum.fudiabetes.org/t/dexcom-138-fingerstick-305/954/25 "2017-06-14T20:17:40Z")
it’s in his arm. ---
**Author:** ![Michel](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/michel/32/387_2.png) [@Michel](https://forum.fudiabetes.org/u/Michel)\ **Post date:** [June 14, 2017, 8:21pm UTC](https://forum.fudiabetes.org/t/dexcom-138-fingerstick-305/954/26 "2017-06-14T20:21:33Z")
> [@TiaG](#): > > well it went down -67 in just ONE reading This is a textbook pressure drop. Most of the time it goes offline after that. But occasionally, it will stay on, except that it needs new calibration. We see one of these about every two weeks. ---
**Author:** ![TiaG](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/tiag/32/594_2.png) [@TiaG](https://forum.fudiabetes.org/u/TiaG)\ **Post date:** [June 14, 2017, 8:22pm UTC](https://forum.fudiabetes.org/t/dexcom-138-fingerstick-305/954/27 "2017-06-14T20:22:36Z")
but why do the low numbers linger when he’s moving around and not not putting pressure on it? He wasn’t sleeping. ---
**Author:** ![Michel](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/michel/32/387_2.png) [@Michel](https://forum.fudiabetes.org/u/Michel)\ **Post date:** [June 14, 2017, 8:27pm UTC](https://forum.fudiabetes.org/t/dexcom-138-fingerstick-305/954/28 "2017-06-14T20:27:22Z")
Once it is dislodged, its new measurement calibration is different. The sensor doesn’t know it was dislodged. Now it is in a slightly different position and the old calibration does not apply. ---
**Author:** ![TiaG](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/tiag/32/594_2.png) [@TiaG](https://forum.fudiabetes.org/u/TiaG)\ **Post date:** [June 14, 2017, 9:32pm UTC](https://forum.fudiabetes.org/t/dexcom-138-fingerstick-305/954/29 "2017-06-14T21:32:55Z")
Well, I wound up having to pick him up from daycare… despite multiple calibrations with higher readings Dexcom stubbornly clung to its notion that he was low. We can’t expect teachers at school to finger prick him every 20 minutes because Dexcom is giving wonky readings. So we are changing out the sensor. ---
**Author:** ![ClaudnDaye](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/claudndaye/32/5_2.png) [@ClaudnDaye](https://forum.fudiabetes.org/u/ClaudnDaye)\ **Post date:** [June 14, 2017, 9:40pm UTC](https://forum.fudiabetes.org/t/dexcom-138-fingerstick-305/954/30 "2017-06-14T21:40:14Z")
This is the cause for lots of our lows in general…the CGM receiver reading one thing, but an actual finger stick reading something else (usually much lower in our case.) ---
**Author:** ![TiaG](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/tiag/32/594_2.png) [@TiaG](https://forum.fudiabetes.org/u/TiaG)\ **Post date:** [June 14, 2017, 9:42pm UTC](https://forum.fudiabetes.org/t/dexcom-138-fingerstick-305/954/31 "2017-06-14T21:42:16Z")
ours is almost always the opposite, which i guess is good – he often reads 40 or LOW even on a CGM but is rarely below 55 on BG meter, luckily. But the weird part is how it just would not accept any followup calibrations as convincing enough to change it’s trajectory. That’s the oddest part. Never had that happen before unless the sensor outright failed. ---
**Author:** ![ClaudnDaye](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/claudndaye/32/5_2.png) [@ClaudnDaye](https://forum.fudiabetes.org/u/ClaudnDaye)\ **Post date:** [June 14, 2017, 9:45pm UTC](https://forum.fudiabetes.org/t/dexcom-138-fingerstick-305/954/32 "2017-06-14T21:45:48Z")
> [@TiaG](#): > > But the weird part is how it just would not accept any followup calibrations as convincing enough to change it’s trajectory. That’s the oddest part. Never had that happen before unless the sensor outright failed. If our actual finger stick is much higher or lower than the reading on the CGM, it makes you enter it twice…that’s what I’ve found anyway. But entering it the second time sets the new reading to whatever new number you entered. When it’s not drastically off and you update it to re-calibrate it, it settles in the middle of whatever it was, and what you are saying it is based off the blood draw. Are you saying you weren’t even able to enter a second one, or that no subsequent entry was accepted? When I have a drastic difference, it just forces me to enter it a second time before it accepts it. I believe someone here indicated it’s a safety feature or something…but I’ve not read anything about it directly. ---
**Author:** ![TiaG](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/tiag/32/594_2.png) [@TiaG](https://forum.fudiabetes.org/u/TiaG)\ **Post date:** [June 14, 2017, 9:48pm UTC](https://forum.fudiabetes.org/t/dexcom-138-fingerstick-305/954/33 "2017-06-14T21:48:45Z")
the subsequent entries were accepted… they just didn’t change the reading. Maybe like 3 or 4 points, but when it’s 40 or 50 points off that’s not right. ---
**Author:** ![ClaudnDaye](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/claudndaye/32/5_2.png) [@ClaudnDaye](https://forum.fudiabetes.org/u/ClaudnDaye)\ **Post date:** [June 14, 2017, 9:51pm UTC](https://forum.fudiabetes.org/t/dexcom-138-fingerstick-305/954/34 "2017-06-14T21:51:19Z")
That is strange. At least in my experience, when it’s drastically off, it never accepts the first entry, but the second one it takes that actual reading. So, if the CGM read 150, but his BG was actually 50 with a finger stick, it wouldn’t accept it the first time, but the second time it doesn’t go in the middle (100), like it does if the BG isn’t drastically off; instead, it just takes the new 50 reading and that’s the new number displayed on the CGM (Dexcom G5 Plat). It’s bizarre that this happened. Do you use the G5 also? ---
**Author:** ![TiaG](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/tiag/32/594_2.png) [@TiaG](https://forum.fudiabetes.org/u/TiaG)\ **Post date:** [June 14, 2017, 9:52pm UTC](https://forum.fudiabetes.org/t/dexcom-138-fingerstick-305/954/35 "2017-06-14T21:52:15Z")
yes, G5. ---
**Author:** ![Michel](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/michel/32/387_2.png) [@Michel](https://forum.fudiabetes.org/u/Michel)\ **Post date:** [June 15, 2017, 1:14am UTC](https://forum.fudiabetes.org/t/dexcom-138-fingerstick-305/954/36 "2017-06-15T01:14:39Z")
> [@TiaG](#): > > the weird part is how it just would not accept any followup calibrations as convincing enough to change it’s trajectory. That’s the oddest part. Never had that happen before unless the sensor outright failed. I had that happen once, maybe 6 months ago. Eventually, Dexcom tech support told me that, when that happens, it means that the sensor input fluctuates so much that it is not able to put a reliable number to which it can apply the calibration. They asked me to swap the sensor, and sent me a replacement. [Previous page](https://forum.fudiabetes.org/t/dexcom-138-fingerstick-305/954.md?page=1)