Issues with the 670G “Looping”

(Sal) #61

I found that the first two problems you describe happened to me quite a bit in the beginning, but once Medtronic replaced my transmitter those problems went away. I think faulty transmitters are a bigger problem than Medtronic might believe.

As for the third scenario you mentioned, that sounds intentional. They don’t want to interfere with what you are in the process of doing. They don’t want the screen to be hijacked with data from your meter if you are in the middle of giving yourself a bolus. Sure, they can make window-shade notifications like smartphones have etc. but at the end of the day they make one pump for everyone, and they have to make sure that everyone from ages 10-95 can use the pump without confusion. Once you exit those screens and go back to the main screen the meter reading will show up.

There is no question that right now the 670 is overly cautious about making sure your CGM readings match your BG readings. It’s the first product on the market that can deliver insulin automatically and make decisions on your behalf. Both Medtronic and the FDA want to be absolutely certain that it’s not delivering too little or two much, and if it gets even the slightest whiff that something isn’t right it will ask you to check your BG. I do believe that future models will pull back on this significantly.

(Sal) #62

Claire, your first question is a direct result of not reading the manual. I know that people don’t like to read manuals these days, but this is not an iPhone. This is not a device for posting silly memes on Instagram. It’s a device that delivers a hormone into your blood stream. Please take the time to read through the manual.

After your first calibration, the pump will require a second calibration after SIX hours. After that second calibration, it will only require calibrations every twelve hours.

There. No need to be frustrated.

As for your second concern, that is indeed annoying as hell, and it doesn’t help that many Medtronic technicians are clueless. Basically, when it keeps asking for your BG, it means that it didn’t accept the one you gave. The problem is that they don’t TELL you that. Only sometimes they tell you that the calibration is not accepted, but many times they do not.

The good news is that once I figured out all the kinks I have nothing but positive things to say about the 670. There are still a lot of annoying things which I believe to be the result of the FDA. I would like to have just one calibration per day and I wish warm-up times were faster.

(Claire) #63

Sal, I hear you and I am aware of what the manual says. My question is if I have calibrated once and then again later, why does it keep asking for BG and/or calibrations at other times? You have answered that by saying it has not accepted my BG. You are right that it does not tell me that.

Thank you,


(Sal) #64

I don’t know the engineering behind the system, but from my experience, here is when it will reject a BG and/or ask for a new calibration:

  1. If BG is too high or too low
  2. If your BG is too far off from your CGM (i.e. your CGM says 120 and your meter says 220)
  3. If your pump is either on MAX delivery or MIN delivery for too long.
  4. If you have a bad sensor
  5. If you have a bad transmitter. (I once went through 5 sensors in one week and then figured out that I must have a bad transmitter. Once I got the transmitter replaced I never again had trouble with a sensor.)

Here are some tips:

  1. When you check your BG with the meter and it’s extremely far off from your sensor reading, DON’T press “yes” on the pump when it asks you to accept! If you do, the pump will then force you to enter a new BG after that to ensure that it’s calibrated. This is especially important at times when you KNOW your BG is going to be far off from your sensor reading, such as during exercise or after eating a bunch of carbs. WAIT until your BG and sensor readings are closer together, then enter the BG. (If your sugar is high and you want to program a corrective bolus, you won’t really have a choice, because auto mode will only allow you to put in the corrective bolus if you give it your BG reading. Personally I “cheat” the system a little, but it’s not recommended.)

  2. Following the above, don’t calibrate your sensor if those readings are too far off. Wait until your sensor stops showing your readings and then calibrate. (i.e. when you get the “calibrate now” message")

  3. If your sensor gets dislodged even slightly, don’t push it back in. throw it out and insert a new one. You can prevent this from happening by putting on both pieces of tape as shown in the user guide.

  4. Calibrate once in the morning and once before bed, that way you won’t get woken up by the pump to calibrate in the middle of the night or during the day while you are in a business meeting. Also, try to change your sensor at least six hours before bed.


For better or worse, when I get in a situation where I just entered a BG and the pump is asking for ANOTHER BG or “BG required to enter Auto-Mode” or stay in Auto-mode I just end up entering the sensor reading, but I do NOT tell it to calibrate. If I think the sensor number isn’t close then I’ll actually check, but this thing asks for so many BG readings throughout my typical day I’d go broke on test strips if I did them all. I get the 2 Hr Auto-Mode min delivery, BG Required one fairly often. Pretty annoying when I’m sitting pretty at 100, no rapid BG drop or rise detected and the thing’s pestering me for a reading.

Maybe one day our pumps will be as awesome as the Ronco Showtime Rotisserie Oven… “Set it and Forget it!”

(Claire) #66


Thank you for putting it down in black and white. I have gradually come to some of the conclusions , but you have organized them in a way that is concise and understandable. Thank you. Now Medtronic needs to address the issues that make the system flawed. If my blood sugar is high and I take a correction bolus, I don’t need to be told that it is high every step of the way down. I shut the high alert off so that I have peace while it is coming down; same thing when it is low. I treat the low at first sight, but am constantly alerted every step of the way up. I also don,t like being kicked off auto mode if it has been on max or min for a while. There is a reason it is on max or min, so I say leave it alone, or alert me at 2 or 3 hours to bolus or eat, as needed.

Thanks again,


(Sal) #67

As a former software engineer project manager (not for Medtronic) I can think of a number of reasons they do this:

The pump starts with the assumption that you (a) are familiar with your insulin to carb ratio and your insulin sensitivity, (b) that generally you are counting your carbs correctly, and © that your endo has estimated what your max basal should be set to.

The pump now has two jobs: 1. Deliver your basal to match your glucose levels 2. Prevent hypoglycemia.

If the pump gets to a point where it’s delivering the max basal for an extended period of time, it can potentially mean that something is not right. It’s not supposed to be doing that, and if it is, it means that there is an anomaly that needs to be looked into. Could it be you underestimated your carbs? If so you need to check your BG and deliver a correction accordingly. Could it be a faulty or uncalibrated sensor? If so you need to check your BG to affirm that it’s working properly. If the sensor is faulty and reading a higher number than it should, the max basal could cause hypoglycemia. If the min basal is going for too long due to a faulty sensor, it can cause DKA. This is why, after a prolonged period of min or max it will prompt you to check your sugar. I have noticed that if within a certain period of time things normalize, it will go back to auto mode without even checking your BG.

Is this system being overly cautious? Probably. But a lot of this is probably from the FDA or fear of legal problems should something go wrong.

As for the alarms, they do give you a lot of leeway in terms of how and when you want alarm warnings. That said, one warning is not sufficient. Suppose you get a warning that your sugar is 250 and you correct accordingly, If an hour later your sugar is 220 should it not remind you again? The pump assumes, and rightfully, that you mighy need another correction.

A lot of these things are annoying and the result of being overly cautious, but I do believe that their next model will ease up on a lot of these things these things. The new model they are working on will not only auto basal but also auto bolus. You will obviously still have to bolus for carbs but it will auto correct in the event of high sugar.

(Claire) #68


You are right of course, just sign me up for the next version right away. I hear that Dexcom makes a system that requires no calibration, but having just started the 670g I will not change. I am still working out the bugs, and you have helped in that regard. The rest is a 47 year T1D frustration that they haven’t cured us!


(Richard) #69

Why change the sensor? I have only had the 670g a month, but all other medronic pumps the last 14 years. Almost always there is a way to resolve without changing a sensor prematurely. They are too expensive otherwise, and there is no point if you will just run out of one down the road. Just think it through. NO one will care like you. REMEMBER THAT! I am old world T!, 40 years of it. so I couldn’t test urine a home at first very efficiently. Learn to know YOU. Nobody at medtronic is even diabetic, so they are all reading off cue cards. My best advice, is try things with your pump. It will be 2nd nature in no time. You will literally speak its language after a couple weeks. Just like riding a bike, you will just understand it and suddenly start making decisions that work for you. Some of those decisions might not be what medtronic or even dr’s would advice. But no 2 of us are the same. So be careful and put that pump through hell… YOu will learn A LOT.

(Richard) #70

the problem is the machine is playing it super safe. One machine for so many people. Plus they are marketing it to type 2 I bet ( which is a joke ) so T1’s like us get screwed. I have learned that unless it asks for a calibration, only enter as a BS reading. If it immediately asks again, just input the same number. Why? because its a legal thing. Down the road someone sues them and they are asked if the pump was very very clear in what it told you it wanted. So a vague ‘enter blood sugar’ is just that… too vague. So yes, it will need work arounds… We all drive our cars different, we all adjust them different… so shall our pumps be different. It is impossible to produce for mass markets otherwise.

(Lyn) #71

Thank you Linda! I’ve been in the loop for a few hours now. When it asked me to enter a BG for the umpteenth time, I entered a number within 2 points displayed on the pump. It worked like magic, I was back in Auto Mode. Thanks again!

(Regina) #72

I’ve been on the 670g for almost a year and auto mode for about 8 months. It has been a big headache. A sensor rarely lasts the seven days and I’ve had a handful fail within 6 hours of putting it in because it won’t calibrate. I called Medtronic and they said that to be able to get the sensors replaced, I have to have them to send back so they can test them. What a huge inconvience it is to one wait on hold for 10 minutes to speak to someone and two to mail the sensors in.

I was on the dexcom for five years and in that time had probably 5 sensors fail and I didn’t have to send the one that failed in. It seems as though they didn’t thouroghly test it. I have really lost confidence in the product and it’s ability to accurately tell me my blood sugar and do what it’s supposed to do.

I am going to probably call tandem tomorrow and find out how much it will cost me to get the pump.

(Linda) #73

You ca turn off the BG notification. It will still show up on the home screen but will not bug you about it. It will bug you eventually to tell you if it is dropping out of automode. Or it will just go away if it decides it is happy now.

(davyboy) #74

Thanks for warning us about the inaccuracy of the 670g sensor. That made my decision to hold off till Tandem releases their closed loop pump. I was araid to go with Medtronic because of the poor quality and reputation of the enlite sensor by them.

(Linda) #75

I have had more sensor problems than imaginable in the one month I am using the 670G pump. Every time I call the Medtronic tech support team they say that I have a faulty sensor, they question where and how I inserted the sensor, and then ultimately they offer to send me a replacement sensor. I have to insert a new sensor. I have found that the sensors are often way off my actual finger stick blood test results. Last night I was woken up at two and four in the morning with what I was alerted as a low sugar. The pump screen read 70. Upon testing each time by finger stick I had the results of 145 and 135, and I was NO WHERE near low. Today before lunch the pump alerted me to a high sugar and the pump screen read 245. I finger stick tested and was at 135. These sensor readings are often inaccurate and I would NEVER trust AutoMode to be in charge of my Diabetes, not when I am seeing such inconsistencies. Medtronic sent me a new transmitter and it did not make a difference. I am very turned off this pump and its sensors and I will probably be using it as just a regular pump. So discouraging…Linda, in MD

(Linda) #76

I’m so sorry to hear about your bad response to the 670G sensors. It’s very interesting how each individual has a different response. My numbers are always spot on or very close so I DO trust automode. It’s a good thing that there are options in life as we are not all alike. Good luck with all your future choices in managing this difficult disease.

(Kathy) #77

Linda - have you tried different sensor sites? I can’t use my abs at all. My SG/BG issues there are very similar to yours and sensors only last about 3 days. However, I do get reasonably good SG/BG results and 6 - 7 days on the sensors) using my thighs (top and outer) and have had success with my outer upper arm. Trying different sites may help.

(Grace) #78

Hello!!! I have also experienced this, but however my pump always resolves the problem. Maybe try only entering your blood sugar once then wait a while. I use this method than it usually I fine. Let me know how it works for you!!

(Kyra) #79

I just want to thank everyone who has posted here. Over the last month or so, I have been having these same issues with only two sensors getting to auto mode and working properly, and about 10 lasting a day or less and most never going into automode. Although I wish none of us were experiencing this, it is also nice to know that I am not the only one because it is so hard to explain and feel heard by those who do not have T1D. The amount of alarms and constant 1-2 hour calls to Medtronic is exhausting, to say the least.

My sensors and automode were working and overall working really well from January - August. After over 16 years with diabetes, my A1cs were starting to get to a good level and I was so happy. And I was so confused in September when this started happening because nothing else changed and I really love automode when it is working - it was improving my health and, thus, my life.

My next step, per a Medtronic rep and some of the comments is to try a different site and I will keep everyone updated. I have been using my stomach area and am honestly quite afraid to use my thigh or arm, so wish me luck! I’m afraid those areas will be more sensitive than my stomach is. Any insight on using the different sites would be appreciated!

(holly) #80

Wow I came in this site just today to ask this very question. My 13yo T1D is having the same problems. I am thinking of calling insurance and going back to dexcom. The auto mode is great when it works but after 3 months she has only been able to wear the CGM continuously once. The stress that it is causing her and is having to stick her so many times is getting old. Called Medtronic and you are right no real answers.