There is no trend arrow on my Dexcom G4

I hoped for the longest time my blood sugar was so incredible stable that the Dexcom had a hard time believing it. But then I googled it and found this page:

Last sentence says:
"A common time where this may happen is when a reading just came back after an antenna icon, question marks, or when your blood sugar is changing rapidly enough where it cannot track it."

I got confused with the last bit and hope someone can help me decipher this part:"..., or when your blood sugar is changing rapidly enough where it cannot track it."

Does it mean the trend arrow is not displaying because my blood sugar is all over the place? Or how am I supposed to understand this last part?

It shouldn’t be happening all of the time. If it is, call Dexcom and have your receiver replaced.

When this happens, you should look at the 1 hour screen. You will see the dots for each 5 min reading, and will likely see the reason why there is no trend arrow. The trend arrow is based on the previous 15-20 mins, so that would be 3-4 dots.

If the last 20 minutes of readings were 80 - 75 - 95 - 110 because you had just eaten, you might get no arrow. On the 3hr screen, that might look pretty flat.

If you check the 1 hr screen, and can verify 'missing' dots for the last 20 min, then the 'no arrow' means it just doesn't have enough data points.

I see no arrow when the sensor is beginning to fail or the sensor would be considered bad and be eligible for possible replacement. I have not had a no arrow display as of yet with a newer sensor (first 7 days), but I have experienced a no arrow nearer to the 14 day mark, which then progressed to the ??? once I went into week 3. My general thoughts are if the sensor is not behaving within the first 7 days (i.e. consistantly faulty readings, showing up or down trends when finger sticks are showing a moderate increase/decrease, repeated ???) then I will call to discuss it with tech support. Always, when in doubt as to the readings generated with your Dex, resort to testing with your glucometer, possibly multiple tests over a 20 to 30 minute time period. That way I can usually rule out is it me (rapid sugar swings) or my sensor (faulty or failing). Good luck!

I have seen this a few times in the first week, but it didn't predict any problem with the sensor. As MegaMinxX pointed out above, if it does happen in the first week, it is in all likelihood a real condition based on real measurements, i.e., your bg really is bouncing around and the meter therefore can't produce a trend arrow from the available (and probably accurate) data.

The trend arrow isn't made simply by measuring anything in-the-moment. It is made by looking at the current reading in the context of recent readings, generating the trend arrow semi-retrospectively. So if you really are bouncing around, there's no available "trend" to report. Sometimes that's real.

On the other hand, if it happens with increasing frequency in the second week or late in the first, then it may indicate that the sensor is beginning to lose accuracy.

This happened right after a new sensor was put in. Maybe half a day or so. Blood sugar was really stable like 5-6 mmol/l for hours and hours and nothing really big going on when I realized there were no trend arrows. Thought it was kind of strange and maybe meaning that blood sugar was so stable the Dex couldn´t recognize a pattern.The arrow came back when blood sugar started to raise again after a meal.

The sensor was a bit crazy the next night telling me four times that I was low when I wasn´t, so I had to calibrate a lot to get the readings more acuurate. Now on the third day it has been more accurate, but never spot on.

Still I wonder what the sentence "or when your blood sugar is changing rapidly enough where it cannot track it." mean in plain english. Anyone care to explain for me?

This happens to us all the time. My son is 3, and has been wearing the Dexcom since he was 18 months old. My son is very small and his blood sugar changes very rapidly. In those cases the Dexcom doesn't "believe" that his BG is changing that fast - like 30+ points in 5 minutes - as if it's trying to decide if that swing is actually possible or whether it's going to go to ???. If it "believes" it, then I will get a double arrow - when it's only changing 15-20 minutes every 5 minutes. It's usually only temporary until the Dexcom can "believe" what's going on - or like I said, goes to ???. Does that make any kind of sense? The Gen 4 is better at tracking his BG, but it still loses track of my son's wild swings too much for my liking (especially in the first 2-3 days).

How often are you calibrating on the first day? On insertion day, I make sure to fingerprick a bunch of times - at least 5-10 times throughout the day - to lock the new sensor onto accurate readings. When I do that, I get good accuracy usually by the end of the day into day 2, and can then do less calibration.

Dexcom recommended that I calibrate more often on the first day, which we do. However, I have to admit that we have calibration challenges with the wild swinging BG (no calibration on up / down single or double arrow per Dex) and the fact that he sleeps 15 hours a day. He hates getting his finger poked while sleeping plus we are trying to create a "safe zone" for him in his room. (I don't know how other parents actually change a pump while their kid sleeps.) However, maybe I have to consider more calibrations on the first AND second day.

Funny - when my son sees the two blood drops after insertion he says "Look Mama! Double arrow blood drop!" Especially when you see the way they display the blood drops, somewhat like arrows. Ha ha.

I know they recommend to not calibrate when it is rising/falling fast, but on the first day or 2, I find that it helps if I do, under this situation:

If I see a fast rise or fall, and I know it's not real, I do a BG test to confirm, and usually enter it. Like nipping it in the bud as it gets off track.

On day 1, I usually enter 4-6, day 2, 3-4 depending on how well it's tracking.

I also like the 'double arrow drops' ! How funny.

Thanks for replies all of you. I was just surprised by the missing arrows beacuse my blood sugar was stable when they were gone. Looking it up it says that´s should not be the case. Hm....

If my sensor is off the first day I calibrate whenever I discover it´s more off than I like. I kind of do the same thing as MegaMinxX, just a kind reminder to tell the Dex it´s losing track. Same on day 2. And I never calibrate when I see arrows pointing up or down but consider doing it the way you describe it MegaMinX.

Excellent suggestion, will try that. Usually once or twice on the first day his BG looks like it's falling off or running up a cliff and then it goes out into ??? for an hour or two before coming back. I'll try and head that cliff dive off at the pass now. Thanks for the help.