First libre change

[betheaton]

Hi - newbie here (2 weeks post diagnosis).
I changed my libre yesterday for the first time and was told to prick my fingers for 24 hours after as they can be a bit inaccurate.
it’s been over 24 hours after I applied it now, but I’m still seeing inaccuracies (5.8 on the sensor and 7.8 BG).
Is this normal or should I be concerned? Any advice would be great!

 

[Lilly]

told to prick my fingers for 24 hours

Just half way thro 1st sensor here. If on the UP it won't matter much; and will only be a concern when you are tending towards hypo levels. I would check when you are expecting to be low or heading low and compare the two then, while assuming you are at the lowest estimated reading. They are only estimates after all and perhaps a couple of FPs will help to indicate a trend.

 

[Bruce Stephens]

it’s been over 24 hours after I applied it now, but I’m still seeing inaccuracies (5.8 on the sensor and 7.8 BG).
Is this normal or should I be concerned?

It depends. If (at the time, so for around 20 minutes or so) your BG was roughly level then that's a bit disappointing. Not, I think, terrible. I'm not likely to do much different if I have a reading of 7.8 compared to 5.8, so pragmatically that seems OK to me.

(Remember that both kinds of measurement have an error rate and that the Libre's measurements correspond to test strips of 10-15 minutes earlier, so use a test strip, then wait a while, and compare that with what the Libre says. And if the Libre shows significant rate of change then don't hope for a close match. And take both kinds of test with a pinch of salt.)

 

[Sally71]

Some sensors are more accurate than others, but to be honest as long as it says high when we're high, low when we're low and in the middle when we're in the middle then that's close enough for me. You can’t expect the readings to be identical because they are reading different things. I find the trends most useful, and the graph of exactly what's been happening between finger pricks. I don't think I’d trust any sensor to calculate boluses from, always finger prick then.

 

[Ljc]

Some people find that if they apply the sensor and wait up to 24 hrs before starting it it’s more accurate , I used to do this myself . It does mean you have two sensors on for a while .

Personally I am ok with a sensor that is up to 2.0 out so long as it reads consistently above or below a finger prick .most of my sensors read below a finger prick.
I tend to check a new sensor out for a couple of days in the morning and when I do my bolus , then when I am happy with it I just do the odd spot check unless my symptoms are not consistent with the scan.

Tip. Don’t rely on sensors when treating a hypo , as you can easily over treat , the interstitial fluid the sensors sample are around 15 minutes behind a blood sample .

 

[Kaylz]

I check via finger prick whenever I bolus no matter how old or new the sensor is as even 1mmol can make the difference of what I inject, my team and consultant agree with that so I don't take notice when people say I shouldn't have it, if your making sure the scan is 10-15 minutes after a prick and there are still large inaccuracies later today then report the sensor tomorrow, they will want 3 comparison readings though xx

 

[SB2015]

I do apply my sensors 24 hours before I need it, mainly because in the early days before they did an update my sensors seemed unreliable for the first day and I didn’t want to lose a day when I was self funding. I have simply carried on doing this.

Like others have said it is the trends that are most important on the Libre, along with the reading together with the arrows which help me to head off hypos and hypers. I don’t worry if the sensor is about 2 units out.

I also always do a blood test if I think I am hypo. My sensors tend to show lower when I am low and higher when I am high. If it is showing me as hypo I am probably hypo or nearly. Best to check, and then my meter had the wait 15 min alarm before retesting. I am often too impatient and underestimate. The alarm stops me testing too soon and avoids me over treating a hypo.

It is great that you already have the sensors. They are a game changer. The patterns will help you to see the impact of certain foods, and they are so helpful when doing sport as it is so quick to get a check on glucose levels during a game.