Thursday, September 21, 2006

DexCom Single Day Glucose Trend Screen Shot

Okay, here we have another type of screen shot that the DexCom software will give you. You can choose to have up to 7 days displayed, but that's too much data to display here, so I just chose one day. The blue circles are sensor BGs, and the red stars are uploaded values from the ultra meter. Those values are used to calibrate the DexCom, and to check to make sure it's tracking along with the ultra BG values. The largest delta is between the first red star to the right, over from the mg/dl Y-axis. The delta is 17 points, which I consider acceptable.

What I can't explain, is the drop in BG from 3:11 am to 3:21 am. The graph shows that I dropped 59 points in 10 minutes, an obvious hiccup. I do a lot of tossing and turning at night, and the sensor is installed on my side, I'm wondering if I somehow disturbed it and the transmitter in such a manner as to cause this glitch.

Anyhow, you can determine from the graph when my meals occured, how high my post-prandial spikes went, how much time I spent between the lower and upper limits of 80 and 200, respectively, and that I need to tune-up my basal rates.


Scott K. Johnson said...

Interesting stuff for sure.

Do you know what the "Gap" indicators mean?

Your overall BG control looks pretty damn awesome to me - but I can certainly respect the drive to get better wherever you can.

Thanks for sharing!

Gary said...

Hi Scott, nice observation.

Those gap indicators show up whenever the wireless receiver is more than 5 ft. away from the transmitter/sensor combo on your body; sometimes I've seen gaps even when only a couple of feet away- it depends on too many variables to list here.

The manual also says they can occur for 'noisy' readings, or if the system determines that another fingerstick is needed for calibration due to a bg meter/sensor value mismatch.

The manual goes on to say that 'noisy' values can occur because the sensor may not be adhered to the skin properly, or something may be rubbing against the sensor (seatbelts/clothing). Noise might also happen with rapidly changing BG values.

The system also shuts down after 20 noisy events and you're supposed to insert a new sensor if this happens.

Anonymous said...

My Type-1 non-pumper husband is also a new Dexcom user. He has managed to successfully use the sensors for ~5 days, and has finally been able to stay within 70-250 for weeks now!

He too has had numerous misreads:

More often his readings are 20-150 points higher than finger test. If the sensor gets wet (sweat or shower sticker leak) it will also give abnormally high readings. Calibrate frequently.

Lower than finger test readings occur when the sensor needs to be pushed back further into body.
(I have to remember that readings will vary with body locations - finger test will trail.)

It is a revolutionary device and I am sleeping for the first time in a decade due to Dexcom monitor! I have learned that potatoes and wheat are sure to send his BS through the roof! But lacking accurate readings, we must remember it can only serve the function of predicting fluctuation. This is the hardest part...Keep up the good work! ;)