@meee,
Welcome to TuDiabetes.
As I read your post, you are switching from G5 (which is not accurate enough to safely dose insulin with) to the G6 (which is safe enough to dose insulin with).
You question about calibration of the G6 I can answer from my wearing a G6 since it came out. It is now driving my Tandem X2 with CIQ technology. The last time I calibrated my G6 is more than 18 months ago. I don’t even have current test strips - BAD on me.
Here is my take on NOT CALIBRATING unless you have problems. Here is my take and the rationale.
CGM Calibration for Beginners (and rationale to avoid Calibration)
Test by finger stick (FS) any time CGM doesn’t seem to match the way you feel.
Verify acceptable deviation according to FDA approvals, ±20% above 100mg/dL and ±20mg/dL below 100. Examples, CGM =200, then FS can be between 160 & 240 and still be fine, or CGM = 70, then FS should be between 50 & 90 with level CGM.
Wait 60 minutes between tests of CGM for validation.
Remember CGM measurements are interstitial fluid and finger sticks are whole blood.
Whole blood & interstitial fluid are physiologically different & 15-20 minutes apart in the movement of glucose.
Call tech support if 2 tests are >20% off, 1 hour apart.
Only enter calibration when tech support instructs.
If you are calling tech support for goofy sensor, request replacement regardless.
Follow tech support to change sensor.
Avoid the calibration rabbit hole of the system requesting multiple calibrations for hours.
Not everyone (some doctors) who prescribed insulin fully understands CIQ.
Finger Sticks (FS) & CGMs don’t play nice together.
First, FS & CGM are only expected to be within 20% of each other according to published standards. If your CGM says 200 then ±20% is ±40 mg/dL meaning a finger stick is fine if it is between 160 & 240. At the same time if CGM says 100 the ±20% would be 80 to 120. BELOW 100 it is ±20 points (mg/dL) without the percentage.
Second, as food is eaten, the food enters the blood stream in various places along the digestive tract. Some enters quickly from the mouth, like granular sugar placed under the tongue. Other foods swallowed quickly may not enter the blood stream until arriving in the stomach. The final absorption occurs in the small intestine.
After food is absorbed into the blood stream, it is ‘checked’ by the liver and then dispatched thru the body in the blood stream.
After glucose is in the blood stream, the glucose moves in the liquid part of the blood (sometimes referred to correctly as plasma or serum - like serum or plasma glucose for the doc’s office or hospital blood test) into the interstitial fluid that moves around all body cells outside the blood vessels. It is this interstitial fluid that CGM sensor wires are in to read the glucose and report it to our measuring devices.
The time for all of the above to take place is usually 15-30 minutes depending on multiple variables including the amount of carbohydrates, proteins, & fats in the consumed food.
It is this 15–30-minute interval and body fluid differences that give significant part to the variation in CGM and FS readings. This is also the reason most comparisons are done when glucose values are demonstrated level by the CGM before doing comparison finger sticks. Wish they would play nice together……
Hope this helps. Please share what you find. It is thru sharing we all learn.
