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Libre 2 first day using lost data

L

lilies32

Member
Messages
19
Type of diabetes
Type 2
Treatment type
Tablets (oral)
Put on the Libre sensor late morning - all going ok until 2 hours after lunch and it came up with hypo 3.7 … I treated the hypo, retested and it rose up but neither of these figures are showing on the graph- puzzled
 
There is a 10 to 15 minute delay between interstitial readings and blood sugar readings. THerefore, the algorithm Libre uses to convert from the Interstitial readings predicts the current reading by extrapolating the current trend. If your levels continue along that trend, it is a very good approximation. However, if the trend direction changes, when the Libre "catches up" it will overwrite the prediction with the true value.
When you treated your low, you changed the trend direction so the historic graph did not show as low.

This is one of the reasons why it is recommended to always test a CGM reported low (or high) with a finger prick before treating. Unless you are feeling obvious signs of a hypo.
 

Ah
 

So if it said 3.7 was that might not be genuine so I need to do a finger prick test?
 
lilies32 said:
So if it said 3.7 was that might not be genuine so I need to do a finger prick test?
Click to expand...
DEFINITELY
(unless you are feeling a strong hypo so need to treat first.)

CGMs are less accurate at high and low numbers so you should always test with finger pricks.
There are other times (such as the first 48 hours after applying) when some of us find that the sensors are less accurate.
 
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