I have used the CGM in the past for Minimed....I decided after I gave up last time (due to similar stuff like this) that I should try again because well, health is important.
After only about 8 hours of it being in, it said sensor lost-it was basically almost on top of the sensor (my pump) and it had been working all day in that area.
I can't deal with this if it keeps happening, these things are expensive and I dont know if it's the thing in my stomach or the sensor but it never wants to work anymore...
Sometimes the sensor can be TOO CLOSE to the pump. Try wearing it a little bit away from the pump. My other suggestion would be to call MM and get their opinion as to what they think the problem(s) may be. If you get no where with the first call, try and call again. Sometimes MM help isn't too helpful, so a 2nd call might get you a person who actually has a good idea of what is going on. If you can't get it to work at all, demand a replacement sensor. It can be frustrating at times...but hang in there and keep trying!!!
The lost sensor alarm probably has nothing to do with it not picking up a reading by the pump. It probably has to do with a faulty minilink or the sensor not being inserted all the way into the skin. I have had MANY conversations with the help desk. If you get short life on the sensor, Medtronic will replace it for you. You should call them for trouble shooting.
Sometimes I get a "lost sensor" alarm when it doesn't seem to make sense, as you've described. My minimed nurse told me not to worry about replacing the thing in my stomach until a last resort.
Here are the steps I try anytime I get a lost sensor message.
Move the pump closer to the general area of the sensor. Ex: front jeans pocket if the sensor is on my front. (Sometimes I forget and stick my pump in my back pocket! Oops!)
Hit "Act", then choose "Sensor" > "Sensor Start" > "Find Lost Sensor".
Wait a few minutes. See if that works.
If that doesn't find your sensor, then I do this:
Unhook the white transmitter from the clear part that sticks in your stomach. (Ex: Pull off any tape you have covering the whole sensor/transmitter site. Squeeze the two sides of the clear thing, and gently slide the white transmitter away from the clear part that goes in your stomach.
Wait 2 minutes.
Hook the transmitter back up to the clear thing that goes into your stomach, just as if you had just put a new one in.
Wait for the happy green light.
Hit "Act", then choose "Sensor" > "Sensor Start" > "New Sensor".
Pretend like you had just inserted a brand new sensor into your body (instead of just reusing what was already there). You will have to do the whole 2 hour wait, then 6 hour test thing, but it should work. And you haven't wasted a sensor!
My minimed nurse said there is no harm in using a sensor for a day longer or so, and the machine really can't tell whether the sensor is new or old - it just goes off of what you tell it.
Of course, do what your doctors/nurses/Mimimed reps have advised you. This is just what I was told to do - and it has worked so far. I have been using my Mimimed CGM for about 2 months now and have not wasted a single sensor yet.
I have the MiniMed CGM as well. Have you checked the expiration date on your sensors? I have a box that is past due and I get a ton of error messages, from "Lost Sensor" to "Bad Sensor," when I insert a new one. I've found that waiting an hour or two after insertion to hit "Sensor Start" on the pump takes care of this problem, and even though they are past due the readings are still accurate.
The constant errors are frustrating, but my control is always way better when I'm wearing a sensor.