Tandem pump and dexcom sensor placement

Hi all,
Do you have to have the tandem t slim pump and dexcom sensor placed on same side of body? Where does infusion set get placed in relation to dexcom sensor? Thanks.


I find it helpful to have them both on our near the same side - I don’t know what it is about denim when I wear it and have my pump in the opposite side pocket from my sensor, it can lose connection. I think the guideline is at least 4" space between them but you should confirm that. So I might have one on my right side of my abdomen, the other closer to center.
Check with your doctor about wearing your sensor on your arm or thigh - I use both successfully but I think you need doctor’s approval in case you have any issues and need a replacement - at one point Dexcom told me they would replace ones from those sites only if my doctor was okay with it. That may have changed by now.
I hope that’s clear.

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Dianne @DFBB, the only restriction" for placement of the Tandem infusion point and the Dexcom sensor is that they should not be placed together. The reasoning for the “too close” is infusion of insulin might somehow, I haven’t figured out how, lower the body fluid glucose level surrounding the glucose sensor. Of interest, there have been trials for devices using a combined sensor and infusion so that both would be inserted with one poke and after expiration of both be replaced.

Other than that, the Tandem pump infusion set, even when pump is serving as principal data receiver, has no relation to the Dexcom sensor, and BLE signals are effective for 30 feet. Just don’t place the pump with its face pressed against your body.

Thank you both for the info. There’s so much to learn that I do often feel overwhelmed but grateful for this forum.

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I place them on either side. Seems to make no difference for me. I am fairly slim. Not much to hide the signal.

I have had them on opposite sides many times as i replace infusion sets every 3 days and sensors every 10 so they get out of whack pretty often. I do find more lost comms errors when i wear the pump on the opposite side of sensor. I also find that most resolve by just temporarily moving pump closer ro sensor to reconnect and going back to business after it reconnected. It does seem to be slightly worse with a transmitter that is coming to the end of battery life.

I am very slim, and if I do not put the pump (not the infusion set) on the same side of my body as the sensor, the sugar readings often fail. I do not get why. I end up having to put the pump in a different pocket closer to the sensor.

I keep the sensor in my abdomen. It doesn’t get bumped or moved around as much there, and with a 10 day insertion time, there’s plenty of time for the previous site to heal before I need to use it again. I put the pump cannula in my limbs.

It makes sense to me. Insulin is pumped into the interstitial fluid surrounding the cannula, to be absorbed into the blood stream and distributed around the body.

The sensor is inserted into the interstitial fluid to detect glucose levels locally at that site. The idea is that the glucose level there is probably more or less the same as it is across the rest of the body. (At least, the central part of the body. Circulation to the hands and especially the feet can be less, particularly in diabetics.)

Insulin levels close to the cannula will be higher than the rest of the body, particularly after a bolus. It takes a while for it to be absorbed and distributed. Cells don’t “drink” from the blood stream directly. They absorb and release everything through the interstitial fluid. So… There’s a chance that the cells close to the infusion site will get more insulin, and therefore absorb more sugar. So if you put the glucose sensor too close to that, the readings could be lower than they would in the rest of the body.

Paul-Gabriel @WearsHats, the theory you explain is what I had logically assumed to be correct. I’ve since proven to myself that the theory doesn’t really hold - I did very little testing.

I had the opportunity to use multiple sensors [Dexcom G6] simultaneously, and I currently place all insulin infusion cannulas and G6 sensors on my abdomen - mapped A-D for sensors and 1-8 for insulin infusion. The sensor readings between the two readers were very close. The manufacturer who makes devices for multiple devices is working on this project.

A factor not often understood s that since the readings are sent to the pump in a radio signal we can’t put the 2 out of the line of sight. When the sensor is too far over to 1 side and the pump is placed too far on the other side the signal will often be blocked. Rather much like listening to your car radio when you drive under a bridge: reduced signal strength cuts the music volume or quality down until you get out the other side.
I have trouble at times if my pump is to 1 side of my pocket full of change, belt buckle, or keys that I hang on the belt. Keep it on the same side without interfeance will serve you well.

Interesting, Dennis. Good to know. But that doesn’t actually disprove the theory.

“Theoretically, this could happen, and that would be very unsafe, so we should tell people to avoid creating that circumstance. The odds may be low, but there are millions of people doing this every day and one error could be catastrophic.” “Well, I’ve done it a few times, and it’s always been fine for me.”

It could be placing the sensor too close to the infusion site, or smoking a lit cigarette while pumping gas, or keeping your phone on while the pilot is depending on radio signals to help land the plane. It’s fine until it isn’t. The rule is there so you don’t roll the dice, however unlikely a critical failure may be.

It is cool that you’re running a test like that, and good to know the data for you has been consistent. But that doesn’t mean it’s not possible. It may be more of a risk in someone else, or in a different site. Poor circulation (either due to a chronic medical condition or just body position and/or constrictive clothing) could make it more likely.

@Dennis , Dexcom, in the USA restricts G6 placement to the belly. See this link.
Dexcom site location (USA):
Where can I insert my Dexcom G6 sensor? | Dexcom
Otherwise, the pump sites and injections should be at least 3 inches away.

Of interest and importance, in several posts on the Child Welfare Information Gateway
(https://www.childwelfare.gov/) child protective services have been notified by ‘mandatory reporters’ of children observed with the Dexcom G6 worn outside of approved locations.

The second concern seen in other social media sites are reports of insurance denying claims for sensor wire removal if it is in a ‘wrong’ location. In a post from Kentucky, the wire was surgically removed, all was thought well until the insurance company asked for the chart notes of the wire removal. The insurance company denied the claim because the G6 had been used inappropriately & negligently.

Bottom line, read an follow the instructions with your devices.