Thoughts on a Calibration Trick

[KarenRI]

I read on another forum that some folks using CGM are waiting 10-15 minutes after taking a BG before entering that number as a calibration. The idea is to make up for some of the lag time between BG and SG.

Anyone have any thoughts on this?

[Mama2H]

I think the number would then be 30 minutes behind? I could be wrong though, my brain is awfully fuzzy lately. I believe that when you enter the number in the cgms it doesn't show up until 15 minutes later.

[Riley'sMom]

wouldn't that kind of defeat the purpose of the calibration?

[KarenRI]

I thought the same thing....seems like it would defeat the purpose, since calibrating takes the lag into consideration.

Not sure at how that idea was arrived at. Just wondering what you all thought.

I'm sticking to what I've been doing...calibrating with current BG's at stable times, reviewing the data every few days, and tweaking basals/ boluses.
Works for me!

Nate has his first A1C tomorrow after starting on CGM one month ago. It will be interesting to see if anything has changed.

[rickst29]

I read on another forum that some folks using CGM are waiting 10-15 minutes after taking a BG before entering that number as a calibration.
Hmmm. I think that Dexcom 'SEVEN' will insist/B] that the latest reading from the meter be "fresh", within 5 minutes, or it will keep nagging you for a fresh reading. But Dexcom communicates with a cable, and queries the meter for the current time as well as the times of recent readings. And when I do a calibration which shows need for a big change, my Dex doesn't seem to do all the adjusting right away-- it seems to continue moving over the next 2 or 3 readings. (That's a guess, it's hard to tell because my bG does really fly around a lot.)

But Minimed isn't like that (it's kinda dumb about calibration), it depends on you to be "somewhat prompt" with the data entry. The actual curve in Minimed it isn't a curve at all, it's just a straight line of slope/intercept versus ISIG. So if you're bG is changing but you GOTTA do a calibration "RIGHT NOW" (why :confused:), it probably [B]IS a really smart idea to wait a about 15 minutes before entering the data with Minimed. (Don't forget that nothing happens until the next reading is taken, so there's an average of 2 minutes 30 seconds more waiting "built in" on any calibration.) If you wait for 15 minutes, it'll be 15-20 minutes before the next Sensor reading actually occurs.

[Lindy]

slope and intercept? good lord that is bringing back some bad high school memories - and I'm sure I flunked that class! :D

[Budapest]

I read on another forum that some folks using CGM are waiting 10-15 minutes after taking a BG before entering that number as a calibration. The idea is to make up for some of the lag time between BG and SG.

Anyone have any thoughts on this?

IMHO this is nonsense.

The CGM is smart enough to make up for the lag between BG and SG on its own and does not adjust SG for until about 15 minutes after entering the BG because it is waiting for that BG to reach the SG.

[bkfkmc]

I read on another forum that some folks using CGM are waiting 10-15 minutes after taking a BG before entering that number as a calibration. The idea is to make up for some of the lag time between BG and SG.

Anyone have any thoughts on this?

If this other forum is the yahoo cgms group, I think that post was referring to when someone was prompted with a "meter bg" and they were during a time of rapid change. This was what they did in order to keep getting numbers and try to allow for the rapid changes for both accuracy and trying to avoid a cal error.

I have never used this approach, but this is what they were doing if I recall correctly. If this wasn't the group that you saw the post on, then maybe it is the same idea.