Dexcom G5 Arrows

On my last trip to my endo, she gave me this sheet on how many points to add to my current BG based on my Dexcom arrows.

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My eyes don’t work as well as they used to. Your post sent me looking for this document. I’m always curious what D-tech suppliers are telling doctors and wonder why they don’t target patients, too.

Any way, I found the source of this document. I hope you don’t mind me reproducing here.


Thanks to both of you–that’s really useful! And yeah, how come this is for the doctors and not for us? I want it on a laminated card I can stick in my wallet or my meter case!

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I’m thinking that Dexcom does not want to give “medical advice.” Their placing this document in an area of their website labelled for doctors yet still available to us patients makes me think it was not an oversight.

The guidelines aren’t too hidden from patients. They are included in the book Pumping Insulin (figure 2.6, on page 18 in the 6th edition). That chart includes the option to increase or decrease the dose by a certain percentage. The two options – in my case, anyway – result in significantly different doses, so I’m trying to determine which works best for me.


At first I was very intrigued by these guidelines. I never explicitly thought about adjusting the readout of my dex. On second thought I am less impressed. When I react to up/down arrows I take into account additional information. For example, I have seen ‘double arrows up’ with glucose tablets or sometimes fruit. Both fizzle out in no time. If I see a ‘single arrow up’ after a meal at an Italian restaurant I won’t get the fizzle. My BG will most likely continue to rise and I have to do something about it. It takes several experiments (eating the same food at the same restaurant) to get it right. I love experiments. The guidelines can be a good starting point. I wish I could tell my gadgets: Watch me eat this Costco Hot Dog. The next time around the gadgets should know how much and on what schedule insulin should be dispersed. The gadgets could even tell me: Wait 10 minutes, if you can. This Hot Dog needs pre-bolus.


I received 2 replacement sensors in the mail this week from Dexcom (each boxed individually) and both boxes included a sheet similar to this, with some but not all of the this information. It doesn’t have the the top green box with the +/- data, includes the “what do the arrows mean” info but not the “possible adjustment” section to the right. Interestingly enough it’s prefaced with “talk through the below scenarios with your HCP to figure out what works for you”.

This is the first time I received this with a Dex shipment.

My latest box of sensors had that new insert too. Their instructions are more conservative and less explicit than these though.

I use a G4 rather than a G5 but was told at Joslin that there wasn’t a material difference in terms of accuracy. So last night I had a long steady climb after dinner that crossed the 160 line after 3 hours or so. I took a correction and the trend line topped out at about 170 falling to 149 after about an hour and 15 minutes right before bed. This is an unexceptional pattern for me BUT I had slanted down arrow and .75 units on board. If I had followed the suggestions on the insert, I would have probably had some sort of snack since 149-75=74 with .75 units of correction on board at less than 2 hours doesn’t seem like a safe place to be.

I woke up an hour and a half later still around 140 and 3+ hours later at 127. At that point I took a small correction and went back to bed waking up at 94.

It seems like a much better idea to look at 3 hour and 6 hour trend lines rather than simply making an adjustment for an arrow.


I’d definitely agree with that. My metabolism behaves very differently at different times of day and a slanted down arrow would mean something very different, in terms of where I’m eventually going to end up and how long it will take to get there, at 9am than it would at 4pm.

Same. I haven’t found the arrows very useful for dosing decisions. I usually only see them about 45 min to an hour after eating something, after a big correction, or if my liver starts dumping glycogen on me. I don’t typically see single or double up arrows unless I’ve done something wrong, so if I see them after eating I know I either under-calculated the carbs or there is a pump site problem. I expect to see the slanted up arrow, but know I have to take action if blood sugar rises to a certain level and the arrow is still showing.

I agree–I wouldn’t rely on the accuracy the chart claims, that’s for sure, but it does give you a more concrete sense of what they mean.

I do rely on them pretty heavily for exercise though. I bike ride with my iPhone in its handlebar holder open to the Dexcom app. Depending where I am along my route and what the number is, the arrows are a pretty reliable indicator of whether I’m going to get to the end of my ride at an acceptable 70, say, or need to pull up and have a couple of lemon drops (I hate those chalky glucose tabs). So 100 with a slanting down arrow halfway through my route is fine; straight down arrow is iffy but maybe ok (60s instead of 70s at the end); double down arrow means cone vision and wobbly muscles by the end so stop right now and open the damn zipper bag.