Just a quick note on misleading finer prick testing and interstitial fluid.

[LittleGreyCat]

As part of my ongoing Libre saga I had an "interesting" moment.
My first Libre read about 1 mmol/L low, so when I scanned it and it showed a 3.4 I wasn't alarmed but decided to do a quick test to see where I really was.

I rushed the test a bit, didn't get much blood and squeezed a bit more.
Test came in at 3.6!

Deep intake of breath, and a rapid retest.

4.4 seems more likely, but which is correct?

4.7 - well it looks as though the first test was way low.

4.7 - yes, I'm not hypo.

My theory is that I was measuring fluid (possibly interstitial?) instead of blood.
The level matched the sensor, but a proper drop of blood was 1 mmol/L higher.

So beware the hasty finger prick!

It does make me wonder how many inaccurate readings I have believed in the past, though.

 

[Winnie53]

Interesting. When I read the term "interstitial", I did a search. This was the result...

https://freestylediabetes.co.uk/freestyle-libre/interstitial-vs-blood-glucose

It would be fun to use the Libre for a few weeks. Perhaps I'll try it when I'm not feeling so broke later this year.

 

[searley]

You can take 2 tests on 1 meter and get different results use 2 and the gap can be bigger.. there are standards that meters have to meet and that is within 15% of a lab result at results above 5.4. Slightly tighter for results below 5.4. Then as you say the libre is not a blood test.. and the results can be slower than a finger blood test... the best you can do is not seek exact numbers. Work on a low/ok/high along with how you feel.

 

[ert]

I always do a finger prick at the same time as a blood test which is why I have faith in my Freestyle Lite.

 

[EllieM]

I recently did a blood test and got 3.9, which was strange because I did not have any hypo symptoms whatsoever. I then did two more tests and got 4.7 and 5.2. It leaves me with very little faith in my meter but unfortunately that's the only meter available on prescription in New Zealand. Still, most of the time it seems OK (successive readings are close). I much preferred my old meter, but I'd have to import the strips from overseas.

On the other hand, the strips are cheap and NZ has only a small population, so I can understand why they want to save money by using them.