Dexcom G5 problems

I am now on my 6th sensor. The first 5 sensors have been problematic with multiple periods of gross errors with readings as much as 100 points +/-. Dexcon has replaced 3 sensors. I have calibrated as per Dexcom instructions, up to 3 calibration 15 min between.
The results most frequently are within the 20/20 rule, however I’m very reluctant to dose on the displayed numbers and always do a finger stick first.
On the positive side the blood sugar trend indicators have almost eliminated lows.

Do people actually trust this thing to treat without verifying with a finger stick?

Is my experience unique, are your numbers more accurate?

Hi Russ3!! I’m sorry ur having issues w ur Dex 5. I’ve been very lucky and have not had any issues w my Dex 5. As a result, I treat almost exclusively w/o a finger stick & directly from my Dex readings. Seems to me that people fall into either the Dex 5 works perfectly and is very accurate or unfortunately the Dex 5 has all kinds of issues , not the least of which is inaccurate readings. I’m sorry ur experience has not been good.

1 Like

Do people actually trust this thing to treat without verifying with a finger stick?

Yes, I do. My G5 is very accurate most of the time. Been using it every day since last Sept. Sorry it’s not working for you. Now, when I go out, I often don’t even take a meter with me. Not to say that it doesn’t get behind by 15 minutes or some, if my bg’s are moving very fast.

1 Like

@Russ3 I have come to trust my G5 almost implicitly. I do find however that the accuracy varies based on location for me. I get my greatest results and longevity on my upper not quite inner thighs, followed by my chest area. Generally I get +3 weeks per sensor with a variance < 10 pts all day w/2 calibrations daily. Your meter accuracy also has much to do with the readings, garbage in/garbage out. Also regarding calibrations, less is more.

One other bit of advice, I definitely prefer XDrip on Android, as I believe the algorithm is much more accurate the the Dexcom algorithm. It also has many more user defined features and can still be linked to your Dexcom account for the Clarity reports.

Hope you are able to sort out your difficulties easily. It really is a great system.

1 Like

And calibration methods are key.
Like right now, I glance at the cgm graph and see it just leveled out at 103 for 30 or 45 minutes. First thought is:
“Great - I should go calibrate it right now. Grab the chance.”

(Last couple days - straight and level is not the norm. The way it goes. Some days are better than other days.)

As I run to grab the meter and calibrate …


BTW I was told DEXCOM releasing new G6 CGM in June or July and I’ve been told G5 users will be switched over soon after. Sensors will stop automatically at 10 days (no extending), no or much less fingersticking, easier installation and other improvements. Dexcom website has info.

@staceyr001 I heard the same from my Dexcom rep, and I will upgrade kicking and screaming. No way am I going to pay out of pocket for a 10 day sensor when I easily get +27 days on a G5 sensor. Plus the G5 is integrated with my pump and I have no. Intention of upgrading until I absolutely have to.

1 Like

When I first started with a Dexcom, it was a black market affair so no training involved except for internet searches. I often made the mistake of calibrating on up and down arrows initially. Then I found TUD and FUD and now… Knowledge is power. At this point feel truly UNLIMITED!

1 Like

What is THE and FUD?

Correction. What is FUD and TUD?

So far I have yet to get 7 days.

Using an arm I’ve gotten 44 days once. Usually it’s around 30 days.

This is TUD.


1 Like

To the original question about accuracy… I’m finding the first 24 hours or so of a new sensor to be very haphazard. I no longer implicitly trust the sensor during that period. I often restart the sensor from scratch once or twice during that period. However, once I get past that period, it becomes quite accurate and definitely dose to it (until it starts dropping out again after ~10-14 days).

I don’t remember always having that much issue within the first 24 hours, but it’s definitely been that way for my last 4-6 sensors. I strictly use the abdomen as described by Dexcom.

Agreed. My first 24 or so hours it can be perfect or variable. I typically use the sides of my belly for placement. During the first 24 hours, if I don’t trust it, I verify/calibrate. After this, during the 14-21 days with my G5, 80% of my calibrations are the same number on the dex as on the glucometer and the other 20% they are mildly different by only 5-10.

Even after that, if I don’t trust the difference, or can account for it (food, exercise, stress,…), I’ll test. I don’t mind testing, but I really am enjoying bolusing for a meal without having too!

1 Like

So far my meter and dex have only been in agreement once or twice. 75% of the time the dex is within the 20/20 rule however that translates to 1/2 to 1 unit of insulin, scary.

This morning my test was within 1 point of the dex. Last night dex was running about 20+ points low and repeatedly woke me with false alarms until I placed the receiver out of range.

Hopefully this thing will level out!

How often are you calibrating? It sounds like you might be over-calibrating.

1 Like

For the last week of so I have been sticking to the every 12 hrs. The exception being when a high of low reading has been stable I then celebrated to bring back in range, at the most 2 extra celebrations.

Visit with my endo.
this am. In range 80% of time with big reduction in lows, 18% above range. A1c at 6.6, an increase, however elimination of lows contributed to rise.

Plan to continue to verify dex with tests until an it things improve.

I find my G5 very accurate. Usually within 5-10 of the meter.


I have found that the less I calibrate it, the more accurate it is.
And to be fair, I am now running XDRIP+, and I only calibrate a few times for a new sensor. Once it seems stable, I only calibrate once every 2 to 4 days.
Doesn’t mean I don’t test my BG. But I don’t calibrate.
I dose off my G5 without concern.
I will obviously know if I feel super far off from the numbers it represents. But if I have the sensor on for more than 24 hours, it is RARE for me.