I always do my “starting a new sensor” calibrations one after the other. I have wondered why if the two are very close to each other, the starting reading will always be around 0.2 mmol/L below the lower of the two readings (so if the two readings are for example 7.5 and 7.8, the pump will typically show an initial sensor glucose level of 7.3). It doesn’t seem to matter in which order you enter the reading. Is this confined to the Animas Vibe system, or does the standalone Dexcom do the same?
I didn’t only refer to the initial calibration. Try to do it with any other, i.e. input the same value twice and see the difference.
I realize that. I was asking a different question, specifically about the initial calibration.
Lexa, So ?? How are you getting on ??? 
Just started tonight. I already had to call tech and they have to send me a replacement receiver already 
I was so scared to start a sensor. It looked so intimidating and painful. Wasn’t too bad. I put it on my arm. Is it normal for it to be sore? I was a little discouraged about if the numbers from dex and my meter would be wacky and way off like some people say at first. So far dex has been really good about an hour after starting it. Have to get used to it still. I keep thinking the numbers on dex are too good to be true lol.
Which of course directly contradicts the Safety guidelines, so yeah, a problem:
Medications
Taking medications with acetaminophen (such as Tylenol® or Excedrin Extra Strength®) while wearing the sensor may falsely raise your sensor glucose readings. The level of inaccuracy depends on the amount of acetaminophen active in your body and is different for each person.
CGM Safety Information | Dexcom | Dexcom
I’ve actually not experienced my sensors being noticeably more inaccurate in the 1st 48 hours, though I once had one of those “sore” insertions and got some pretty crazy readings the first day. When I eventually took the it off I could see that the adhesive patch was blood stained and I’d obviously hit a capillary. Dex no likey.
One thing I have noticed is that mine seem to get more accurate after rolling over into additional sessions on the same sensor. The third session—beyond day-14—it seems to track within a point or two of my fingersticks (Bayer Contour-Next) day after day. Which is frustrating because that’s about the point at which, no matter what I do with Skin-tac and medical tape, the thing just can’t be made to stick on any longer and either falls off on its own or I yank it off just so I don’t end up having to put a new one on in the middle of the night. The limiting factor for me is always adhesive longevity rather than sensor longevity.
Proper taping is the only solution. I am on my 20th day with my current sensor, waiting for the battery on the G5 to die. The transmitter has been running since Feb 19th, i.e. 3 months and 2½ weeks.
I have realized that the change of the Tegaderm in my case is a good solution. Of course I can’t do it on my own since somebody needs to hold everything in place while the old tegaderm is being pulled off.
That has not been my experience.