Meter readings confusion

[dannyw]

I come back to a point I made elsewhere on this topic though. Diabetes is not a condition of exactitudes. So one meter reads differently from another? So what? As a T1, you had to use urine and test tubes and then visual colours to guesstimate what was going on. Now you get an electrochemical reading that, due to reading to 0.1 of a mmol, people believe to be "accurate".

Given that timing, absorption rate, test locations and measurements are all variable and not at all "accurate" then the numbers on blood glucose meters can only ever be a guide. The best you can hope for is consistency. Getting hung up on the accuracy of the numbers or even the accuracy of the numbers isn't going to dramatically change your life. If you target 5mmol/l on a blood glucose meter, then, based on the current and future ISO requirements, you will be measuring within the range you want. with it is 4, 5 or 6 really doesn't matter a vast amount. For a type 1, what's more important at that point is the direction of travel.

Although I completely agree with this the fact that certain meters read consistently high or low does make a difference if on insulin and are a driver. We are all aware of the DVLA guidelines and how strict they are ( as they should be ) so a meter that read lower than it should can make a difference.
I too look for trends though rather than worry too much about single readings and hopefully with technology moving so fast, the margins of error will reduce even further in the future.

This is why there's the five to drive guidance, and equally, if your meter shows you at 4.8, the DVLA guidelines say you can still drive. Even if the meter is reading 20% high, and your number is 4.5, with a real number that is 3.6, your meter says 4.5 (so no issue on that point) and you aren't technically or clinically in a hypo state at 3.6!

Again, I agree. My point was the other way around though really. If say, you had a meter that read consistency lower than another, it may affect your freedom to drive. If you tested your blood and were between 4 & 4.5, you'd need to snack and increase levels whereas your actual readings may be over 5. OK, not going to make much of a difference to most people but if you kept your numbers tight, it could occasionally be a pain.

 

[Administrator]

I finally found the ISO (2013) Table showing Error vs readings in mmol/l as requested above at
http://www.diabetes.co.uk/blood-glucose-meters/blood-glucose-meter-accuracy.html
It may need updating soon for ISO (2016)

http://www.diabetes.co.uk/blood-glucose-meters/blood-glucose-meter-accuracy.html has been updated!

 

[Oldvatr]

http://www.diabetes.co.uk/blood-glucose-meters/blood-glucose-meter-accuracy.html has been updated!

OOPS! The figures are not what I expected. The first chart is titled ISO 2003, but the second is for 2013.which is the new ISO coming into effect in 2016 hopefully (confused?)

Again a quick check of the 10 mmol/L and 20 mmol/L rows, does not tie in with my understanding of error, and does not match either 20% (2013) or 15% (2016) I was expecting it to be<< + / - percentage of reading>> but it clearly is not in these tables. I have scoured the web for a chart to compare against, but have not found one. However, the examples given in the text of an ADA report has the same interpretation that I do.

 

[Administrator]

OOPS! The figures are not what I expected. The first chart is titled ISO 2003, but the second is for 2013.which is the new ISO coming into effect in 2016 hopefully (confused?)

Again a quick check of the 10 mmol/L and 20 mmol/L rows, does not tie in with my understanding of error, and does not match either 20% (2013) or 15% (2016) I was expecting it to be<< + / - percentage of reading>> but it clearly is not in these tables. I have scoured the web for a chart to compare against, but have not found one. However, the examples given in the text of an ADA report has the same interpretation that I do.

Ah, the ISO standard was actually agreed in 2013 and that may be where the confusion lies. In regards to the readings, will send to the editor. Be back soon on this!

 

[AloeSvea]

Even though I am a T2, and not on medication, I have experimented extensively with diet and exercise's influence on my BG - and I am seriously much happier doing that when the BG readings seem more aligned to fact! Especially when keeping an eye on BG in order to keep an eye on organ health - thinking of what Jenny Ruhl and Dr Bernstein write about 'safe levels' to aim for before organ damage really sets in.

I see from this thread, and reading the linked articles, that I may be expecting the unexpectable at the mo'? ie accuracy. (Very interesting to know it's probably the test strips, and not the meter.) What a shame! I really like it when all the numbers match up in a logical way (ie Home meter BG readings, with average home meter BG readings, with HBA1c and lab BG readings.) And I hate having to muck around with numbers anymore than I have to!

Bring on greater accuracy!

Thanks heaps again for the links in this thread.

 

[Oldvatr]

I found thid on the web, and it may explain why one of my meters consistently reads higher than the other.

http://www.joslin.org/info/plasma_glucose_meters_and_whole_blood_meters.html

Neither of my meters refers to how it is calibrated in the literature. @Administrator is it possible for DCUK to follow this up and produce a table of the more common meters to provide clarification and possibly add it as a sticky thread.

 

[Oldvatr]

@Administrator Hi I see the tables on the DCUK site for meter accuracy wrt ISO standards still appear to be incorrect Where do the figures come from? Surely the error is +/- n % of reading?