G6 now wants calibration?

Dexcom recently handed my account off to CCS Medical. It may be because I’m a Medicare client. I recently got my first shipment, and inserted my first sensor.

Now, I told you that so I could tell you this: I now have a calibrate symbol on the home screen of my iPhone app, and it’s been prompting me to calibrate at least once a day. Usually it’s just one calibration, but sometimes it’s two. It seems to me that Dexcom either pushed a calibration upgrade to my app, or it was embedded in the new batch of strips, because I have never had that blood drop symbol before since upgrading to G6. I got neither an e-mail nor any paperwork announcing this change. Interesting also that this has happened after Medicare stopped covering test strips.

Has anyone else had this happen, and if so, have you gotten any background that I haven’t seen yet?

When you started your sensor session, did you use the sensor code stamped on the applicator label? Or did you start your sensor session by selecting “no code”?

According to the G6 set-up guide, if you started your sensor session by tapping “no code,” you will need to calibrate twice at the end of the warmup period, 12 hours later, and again another 12 hours later, then once every 24 hours.


I took a photo of the QR code on the label, and the app accepted it. I’ve never used ‘no code’.

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I agree with @terry4, that it appears to behave as though no code entered. After day 2, should prompt only once/day.

I have always used direct input, not QR code. You can call Dexcom support to see if they can explain why it didn’t work. Should have nothing to do with Medicare.

On receiver, under Settings -> sensor info, it unfortunately does not show code, which I think it should.

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My first G6 sensor session is still about a week away, so I don’t have any first-hand experience, please excuse my inexperience. Did you take a photo of the sensor code for later reference or did the act of taking the photo enter the code into the app?

There are two concerns here.

  1. Dexcom handing you off to CCS Medical without authorization. Something is fishy here. There is a group of about 10 in my support group and we all use Medicare with Dexcom.

  2. Are you using another device to receive the CGM data in addition to your phone? How did you start your session?

Dexcom is trying to transition to DME or Pharmacy for everyone. With G5 they had to include bg strips, so they took on medicare to make sure shipped together. G6 does not require strips to be bundled.

The G6 is approved to be more accurate than G5, and the code is what allows for variations in batches of sensors. G5 required blood checks, and Medicare only approved to cover G5 if it was purchased with bg strips for calibrations. It was only Medicare that required G5 + BG strips to be bundled.

So its different with G6. You can still get strips, but as separate purchase, as RX item.

When G6 prompts for BG, it means it doesn’t know the code, or it suspects the reading is off for some reason.

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I always take a picture of the numeric code and I also put the numeric code in by hand. Never had any problems when putting the number code in by hand.

“…did the act of taking the photo enter the code into the app?“

Yes. When you select ‘take a photo’ for code input, the square brackets appear on the screen, you center the code symbol between them and take the photo. If it’s accepted, you see the big green check mark on the screen. I’ve done both methods of input without a problem up to this point.

Ok, a couple of points, one of which may have the answer to the conundrum.

First, the handoff to CCS wasn’t without authorization. Dexcom called me and told me it was going to happen, then CCS Medical called to set things up; this didn’t take much effort, as I’m already a customer for pump supplies. The only notable thing was that, for the second time in 2020, I spent most of a month without a sensor shipment. Damned if you do, damned if you don’t. :expressionless:

Next, I may have brought the calibration issue on myself, but not in the ways we’ve discussed thus far. As I said, the sensor code was accepted when I entered it. However, after the warm-up, the first reading was over 200. To make sure this was correct, I did a bg test, which showed I was actually at 110. Thank goodness for spidey-sense. So, in an attempt to get things back on track, I calibrated with the meter value. I can’t remember if it asked for a second value at that point, but at some point that same evening, the beeper went off, and that’s when I noticed the blue blood drop symbol with a red 2, asking me to recalibrate with two test values. So, my next question is, did calibrating just after warm-up cause the CGM to automatically assume ‘no code’?

The error between the bg measurement in the sensor and the manual stick caused Dexcom to believe something unsavory was going on. That’s why it wants you to input manual readings. It doesn’t feel good about its sensor accuracy. Neither should you.

If you keep seeing inaccuracy, you will just need to pull out the sensor and swap it for a new one.

Sorry to belabor this point but I’m learning things from your post. At times, you’ve entered the sensor code using the camera. Does that record and store a photo on your phone that you may later reference to see what the actual code was for that session? Or was the function of the camera simply used as a way to input the code number into the app without a photo being stored on your phone?

To the crux of your situation, I think calibrating with a value that is quite distant from the sensor’s current value may cause the algorithm to require more calibrations. I’ve read many users are loathe to put in any calibrations in the first 24 hours in order to avoid creating undue “calibration neediness.”

These users often report that, after the first 24 hours or soon thereafter, the sensor starts reporting values close to actual finger stick BGs without the need for any calibration.

By the way, I recently changed from the third-party supplier, Byram, due to their tendency of what I call “calendar creep.” Without extra supplies on your shelf, calendar creep leads to days without the service of any CGM, unacceptable to me.

Instead of shipping every month 30 days after the last shipment, it slipped each month to 35 or 40 days for what seemed to me as an unending list of bureaucratic reasons. I switched to US Med as they ship 9 G6 sensors and 1 transmitter every 90 days. (I have no relationship with this company other than as a customer presently happy with their service,)

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The sensor paper has 4 digit code, and a QR version. So photo is more like a scan.

Check this link for how it looks.

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I’ve had this exact same issue occur on a sensor a couple of weeks ago. Sensor showed a high BG (200+) and fingerstick was showing something else. So I immediately calibrated. I think this triggered the Calibration icon remaining active for the remaining sensor life, < 10 days. I think I made a few more calibrations on the first and maybe second day of the sensor and after that the sensor was accurate so no need to calibrate, despite the Calibration icon still showing.

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Thank you for sharing! Always good to know I’m not the only one, especially when things go askew. Now I have to wonder just why this happened. :wink:

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Odd. I have calibrated early in sensor life, yet have never been forced into another calibration. Mine weren’t that far off, so perhaps there’s a cut-off point that leads to more calibration requirements.


@Terry4, here’s something else odd. What Dexcom says here would lead me to believe that every sensor has a different code, but experience taught me differently. About two months ago, I was happily restarting sensors; it was the way I kept myself supplied when shipments were either late or nonexistent. Here’s the kicker: the last shipment of 3 sensors that I received from Dexcom all had the same code. It seems to me that either their advice about not restarting sensors is provably false, or they were dumping old stock. Just ftr, all of those sensors started and restarted like a charm. My last restart attempt, with a newer one, was a bust.

Was the new sensor used with same or newer transmitter? We definitely know that newer G6 transmitters make it harder to restart.

@MM1, it was the same transmitter I had been using with the other, successful restarts. I have a new one that I will need to start using, an 8L SN, as I’ve gotten a notice that the battery is running out.

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