A man with two watches never knows the correct time.....

DaveNN said:

A 10% variance is a little excessive and, whilst I must check the tolerances, something appears to be amiss.

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It's really not, but in your case you're talking about even less of a variance (+/- ~5.4%).

If you're concerned, then test until you feel more comfortable with all of the readings. Just remember that even the best meters will have some variance (<10% is considered very good), and two drops of blood won't always yield the same reading.

@TorqPenderloin is right about no two drops of blood being the same:

http://www.nytimes.com/2016/02/23/h...a-persons-blood-is-the-same-a-study-says.html

We don't worry too much about it. It's not worth it.

DaveNN said:

Agreed though I do question your figure...and a proper blood test would be the only way. however the variance is approx' 10%, albeit on a lowish figure. If we use the range and took it as read that the meter will under/over measure equally then my BG could easily be 5.5. or 7.4mmol At times like this I yearn for the day when the Glucowise system is available.

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You had a reading of 6.8 and 6.1. In theory, if your reading was actually 6.45 (right in the middle), a variance of +/- ~5.4% could yield your two readings.

As far as the 10% accuracy figure, it's not something I've made up. There are several comparison studies of various glucose meters that document similar figures. However, I would agree that a variance of 10% would be ridiculous and something I personally would throw in the trash (my Accu-Chek Aviva Expert meter is much more accurate than that).

If you went by one test for all your different foods, just how will you discover, how much of a certain type of food is ok, and what is not.
Testing is about seeing patterns of how your glucose levels respond to what amount you eat and getting the balance right between how much over time.
Not only are two blood samples never the same but over time depending on insulin resistance, it changes, to how you are coping with control.
In the end when you know how not to spike, means that testing becomes a way of how you are improving.
I know now that if I was to test before and after every meal, that my levels would be always in the normal level range.
And I would have sore fingers.

DaveNN said:

Yep.
In this respect, how on earth do those diabetics who require insulin get on?

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Just go from the first bg reading unless alarm bells ring and the reading doesn't make sense, in that case I'd always do a second bg test.

If I test and don't much care for the number, I try not to test again, unless it's one of those, "Are you having a laugh go?" numbers. I don't test again if I have a particularly spiffing number, so surely they all average out over time.

Your controlfreakery is way, way much worse than mine. I thought that wasn't altogether possible.

I found this interesting reading
Glucose Biosensors: An Overview of Use in Clinical Practice
Not to sure if you will find it relevant though.
"
The measurement of blood glucose levels is carried out using various glucose biosensors for the screening, diagnosis, and long-term management of patients with diabetes. Since the prevalence of diabetes is increasing, novel glucose biosensor technologies, including POC devices, CGMS, and noninvasive glucose monitoring systems, have been developed during the last few decades. Recently, the value of glucose biosensors at the POCT by medical professionals and the SMBG by patients has been widely accepted. Rapid and effective corrections of blood glucose levels are based on regular glucose measurements using glucose biosensors.

Glucose biosensors have evolved to be more reliable, rapid, and accurate and are also more compact and easy to use. Research for advanced technologies, including electrodes, membrane, immobilization strategies, and nanomaterials, continue to be performed. Despite the impressive advances in glucose biosensor technology, there are still several challenges related to the achievement of reliable glucose monitoring. The ADA recommends the accuracy of a blood glucose POC assay to be <5% of the measured value. However, many POC devices do not meet this criterion. Biosensor technology is less precise and less accurate than the methods used in central laboratories .

A more systematic evaluation of the analytical performance of glucose biosensors is recommended to ensure reliable and accurate testing. Analytical requirements for suitable hospital or home POC devices include good linearity, precision, and correlation when compared to a clinical laboratory reference method as well as resistance to common interferences. The calibration of the devices and quality control should be performed on a regular basis according to the manufacturer’s instructions. User-dependent factors can also affect data quality, and by extension, treatment outcomes. The most commonly cited problems are incorrect use of the test strip, lack of quality control procedure, fingers that are not clean and dirty devices. Various studies have shown that education and continuous training can reduce errors caused by the aforementioned factors and improve measurement performance .

Therefore, in addition to further technical improvements of the biosensors, standardization of the analytical goals for improved performance, and continuous assessment and training of lay users should be established."

here is a link to the article

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3292132/

Just wondering why you think the Glucowise will be any more accurate than the finger pricking devices @DaveNN? Reading the website bumph, they are adhering to the same ISO standards that the blood meters use, which allows for a 15% variation. I haven't seen any form of Clarke or Consensus Error Grid for these devices so it's hard to determine what the accuracy is likely to be...

DaveNN said:

Yep.... Worrying doesn't help.

Accurate monitoring does,

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I always respect what others do that is their prerogative but there is no "one size suits all" We listen here to others experiences then based on that find out what suits us personally
I found testing was to unpredictable when it came to food I started to do it but soon found that the same foods gave me different levels every time so I stopped because I never knew what was right and I knew I could quickly become an obsessive tester
I had already cut out the starchy carbs and sugar stuff when I knew I was prediabetic but I have not cut out anything much else since I was diagnosed T2 at just over a level of 7. I am just moderate on saturated fats...I don't eat red meat.. have good oils I eat all vegetables and salads which I love but not a lot of fruit I may have an apple or a satsuma if I really fancy one even some chips sometimes.. I just test now a couple of times a day probably morning and evening but not every day just to keep an eye on my levels which I am happy with that's just how I do it but I know it would not suit everyone

DaveNN said:

....I know..and agree totally. However, I can't ever beat myself up for keeping an eye on myself ;-)
The first reading threw me a little, hence the re-test.
It's all relative though, as at least it wasn't in double digits, I suppose.
You are quite right about the good numbers though I did a test the other night where my BG was normal a bit after a deliberate binge and then rocketed way after..
A meter reading is no better than a MOT...it's only relevant for that particular day or even time.

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Your final half sentence is it. Meters give us immediate feedback on current activity, so measure the small steps. Once we have a handle on the route we need to take, with experience, we can sometimes vary the pace length (size or content of our troughs), and still be on tract by the time we reach the next staging post.

Looking after yourself is one thing. Micromanagement-to-standstill is what happens in the public sector isn't it? Who needs that?

(Apologies to any decent public sector Managers out there.........)