SD Codefree test meter.

[Will D]

Hi,

As I have mentioned elsewhere, I have been using for the past couple of weeks some old test strips (from 2011 - so well out of date) in a Freestyle Optium meter, until the SD Codefree kit that I had ordered arrived.

This morning I did my usual fasting BG test, and the result was 4.8, which was a fraction higher that usual, but not a surprise.

Shortly after the post arrived, and the Codefree kit arrived.

I set the meter up, used the test strip to check the meter, it showed ok, so then I did a BG test, and it showed 5.5, which I was surprised about!

It was disappointing, as it indicated that the out of date Freestyle strips were indicating lower than realistic readings, and thus all of my prior tests were in reality higher than I had thought.

After thinking about things for a short while, I decided to retest with the Codefree meter, which I then did four more times, one after another, all using a blood sample from the same drop of blood from my finger - the readings were 5.1 5.6 5.3 & 5.5

Now I'm beginning to doubt the accuracy of the Codefree kit completely, surely the variation must be outside of the acceptable accuracy? Has anyone else had similar problems? I know that the meters are supposed to meet some standard of accuracy before they are permitted to be sold, but I've not actually looked for the details of that yet...

I'm interested to know if I've just happened to have bought a bad meter, I've not spoken to the retailer as yet, hoping for other's input first.

Thanks,

Will.

 

[phil1966]

Could it be that the Codefree is calibrated as plasma equivalent and the older freestyle may be calibrated as whole blood? (plasma equivalent meters read about 10-12% higher but are closer to what you'll get from a medical reading)?

see here for a bit more info: http://www.joslin.org/info/plasma_glucose_meters_and_whole_blood_meters.html

 

[Will D]

Thanks phil1966 for your reply, I followed the link you included and read the info, it appears that the page hasn't been updated since 2002, so it's possible that all meters now indicate readings on the blood plasma basis? I wonder that as I read the manufacturer's literature afterwards and could find no reference to it at all.

That still wouldn't explain the variation in consecutive readings, and having also just looked at the reviews on Amazon (not the best time to do that obviously!) there are a considerable number of people with the same complaint.

I'm shortly going to do some more tests, and see if I can be very precise in how I offer the blood sample to the test strip, to see if I can get repeatable readings - if that doesn't work then the meter is not safe to rely on.

If the problems continue I shall contact the manufacturer directly to see what their thoughts are..

I have an appointment tomorrow with the DN, so I'll take it with me and see if I can compare it with their meter - I shall also take my Optium meter with an out of date strip and compare that too...

Nothing is ever straightforward, it seems!

Thanks,

Will.

 

[mrspuddleduck]

No sure about the accuracy of the metres but were those test strips actually 4 years out of date?
Just looked at the codefree manual, as you were using the same drop of blood,
" consider your result if.... More than 20 seconds elapsed from sample collection to measurement commencement. Evaporation of the blood sample can cause a test result that is higher than the correct level" Could that have influenced your results??

 

[Will D]

Just as a followup, I just scrubbed my hands and did five more tests, very careful to offer the blood sample precisely to the test strip the results were 5.2 5.2 5.0 5.5 & 5.3 - so still rather too variable.

 

[Will D]

No sure about the accuracy of the metres but were those test strips actually 4 years out of date?
Just looked at the codefree manual, as you were using the same drop of blood,
" consider your result if.... More than 20 seconds elapsed from sample collection to measurement commencement. Evaporation of the blood sample can cause a test result that is higher than the correct level" Could that have influenced your results??

Hi mrspuddleduck, the Freestyle strips actually expired in September 2012, having just checked, but the codefree ones are October 2016 expiry.

The age of the blood drop may have some relevance, but it is clouded a little as I squeezed more blood out of my finger between some of the consecutive tests, which means that I need to do more testing, but that will have to be later now...

Thanks for pointing that out!

Regards,

Will.

 

[Brunneria]

Just as a followup, I just scrubbed my hands and did five more tests, very careful to offer the blood sample precisely to the test strip the results were 5.2 5.2 5.0 5.5 & 5.3 - so still rather too variable.

I actually think those results are very accurate.

Meter manufacturers are required to produce meters accurate to within 15% + or -.
That is, I believe, an industry standard.

In which case, your Codefree is doing quite well.

Assuming your true reading would be (say) 5mmol/l
then your meter could happily read as low as 4.25 and 5.75 and still be within tolerance.

Home testing with a self funded meter is more about trends and patterns than individually accurate readings.
I've found the best thing is to test regularly, record results with a food diary, and look for trends over time, or repeating patterns with particular foods.

There are a lot of factors at play, including portion variation, time of day, varying insulin resistance, tiredness, recent exercise and stress levels, so I am sorry to say that it will never be an exact science.

 

[Will D]

I actually think those results are very accurate.

Meter manufacturers are required to produce meters accurate to within 15% + or -.
That is, I believe, an industry standard.

In which case, your Codefree is doing quite well.

Assuming your true reading would be (say) 5mmol/l
then your meter could happily read as low as 4.25 and 5.75 and still be within tolerance.

Home testing with a self funded meter is more about trends and patterns than individually accurate readings.
I've found the best thing is to test regularly, record results with a food diary, and look for trends over time, or repeating patterns with particular foods.

There are a lot of factors at play, including portion variation, time of day, varying insulin resistance, tiredness, recent exercise and stress levels, so I am sorry to say that it will never be an exact science.

Hello Brunneria,

Thanks for your reply.

As I think I noted somewhere, I hadn't checked the intended accuracy of BG meters in general, but have subsequent to your post. At present, other than for low readings, the required accuracy is +-20%, which is changing next year to +-15%, as you noted. For low level readings the requirement is +- 0.83mmol/l (below 4.2 mmol/l changing to below 5.6mmol/l in 2016).

I think that that is an unbelievably poor standard to have to set, but as you say, it is not so bad for comparing readings day to day or before and after meals etc. However inaccuracy is one thing, poor repeatability is something else entirely, and if one is trying to check the effects of particular foodstuffs on one's BG level, poor repeatability renders that impossible.

The last series of tests only(!) had a maximum range of 0.5mmol/l, so as flagged by mrspuddleduck, I need to repeat the tests with "fresh" blood again before I can confirm the variation.

If the meter - when used properly and consistently - offers repeatable results, then I shall be happy with it, if not I shall be reverting to another meter (I think that I also have a bayer meter somewhere...)

Thanks,

Will.

[edited to tidy post a little]

 

[Randburg]

Hi Will,
Over my 5 years of being a Diabetic type 2, I have used 4 different brands of meters, and have not found one that gives you accurate readings, they all varied about 10 -15 % on readings taken.
As @Brunneria said you should use the meter to pick up trends.
The only true indication is a HbA1c blood test
The best meter is the one that the strips are the least costly, if you are paying for them as I do
All the best

 

[satindoll]

I've found my Optium Exceed is pretty accurate, on my last HbA1c I took it with me and tested with a drop of blood from the same needle the nurse used to take her sample it registered 5.5, then my results came back at 36mmol which equates to 5.4, so am happy with the difference it shows.

 

[catherinecherub]

This article explains some of the problems with meters.

Why meters can't tell us our blood sugar readings.
http://www.healthline.com/diabetesmine/why-meters-cant-tell-us-our-blood-sugar-levels#1

 

[Will D]

This article explains some of the problems with meters.

Why meters can't tell us our blood sugar readings.
http://www.healthline.com/diabetesmine/why-meters-cant-tell-us-our-blood-sugar-levels#1

Thanks for your input catherinecherub, I read the article and it largely agrees with other articles and posts that I have read this afternoon. I do understand that increased accuracy - particularly greatly increased accuracy - would inevitably lead to increased manufacturing costs, and thus increased retail prices, which no-one would enjoy, but as I said earlier, the lack of repeatability I find completely unacceptable.

I suspect that a lot of people would expect and treat the readings given by the meters as a very good indicator of how they are controlling their condition, whereas if my meter is typical of those generally in use, they are potentially much worse than useless, particularly if one isn't scrupulously careful about carrying out the tests.

I'm going to go and carry out some more tests in a moment, ensuring a fresh blood sample each time, to see how the meter performs then. I'm very much hoping that the repeatability is good, then I shall be happy.

In that case, it will be easy to test it against the DN readings, and use a correction factor to get a more accurate reading. I suspect that that will only work to some degree, as the two meters readings will undoubtedly vary by differing amounts, depending upon the particular BG level.

I can see that different packs of test strips are likely to introduce differing readings in themselves, but one would hope that they are at least reasonably consistent within the same batch...

Regards,

Will.

 

[Will D]

Right,

Just done three more tests, wiped away first drop of blood, then tested each time with three fresh drops of blood squeezed out then wiped away prior to the next drop. Hands thoroughly washed prior to testing, and a clean fresh piece of kitchen towel used as the wipe. The three results were 5.0 4.8 & 5.1, so I'll consider myself satisfied with that.

As an addition - something that I meant to post earlier: having read additional parts of the manual, I found tucked away that the Codefree meter does in fact give a plasma-equivalent reading, as per phil1996's suggestion earlier (as does the Optium meter).

Congratulations to those who have read all the way to here!

Regards,

Will.

[edited to add paragraph]

 

[AndBreathe]

Right,

Just done three more tests, wiped away first drop of blood, then tested each time with three fresh drops of blood squeezed out then wiped away prior to the next drop. Hands thoroughly washed prior to testing, and a clean fresh piece of kitchen towel used as the wipe. The three results were 5.0 4.8 & 5.1, so I'll consider myself satisfied with that.

As an addition - something that I meant to post earlier: having read additional parts of the manual, I found tucked away that the Codefree meter does in fact give a plasma-equivalent reading, as per phil1996's suggestion earlier (as does the Optium meter).

Congratulations to those who have read all the way to here!

Regards,

Will.

[edited to add paragraph]

As others have said, I think you have just encountered "one of those things". It's also wholly likely if you mirrored the tests you've been doing on your Codefree on your other meter, you would see similar results, in terms of variance. Yet a further variation cam come from one batch of strips to another; whichever meter you use.

Because of my personal circumstances, whereby I am periodically overseas for months at a time, I usually end up buying around 20 tubs of strips or more when I place an order. I can't source the Codefree strips overseas, so I have to go "tooled up". Whilst it's a bit of a hit to the pocket, it does mean I can achieve a decent level of consistency for a few months.

Good luck with it all.

 

[Will D]

As others have said, I think you have just encountered "one of those things". It's also wholly likely if you mirrored the tests you've been doing on your Codefree on your other meter, you would see similar results, in terms of variance. Yet a further variation cam come from one batch of strips to another; whichever meter you use.

Because of my personal circumstances, whereby I am periodically overseas for months at a time, I usually end up buying around 20 tubs of strips or more when I place an order. I can't source the Codefree strips overseas, so I have to go "tooled up". Whilst it's a bit of a hit to the pocket, it does mean I can achieve a decent level of consistency for a few months.

Good luck with it all.

I don't know which meter you use AndBreathe, but at least if you use the Codefree strips, they aren't too much of a strain on the pocket - they are a quarter of the price of the Freestyle ones - I'm glad that I've managed to make the Codefree meter repeatable enough now that I can trust what it tells me.

I'm sure that my other meter does vary too - but it wasn't by much when I first started using it again, as it was something that I tried as testing was a bit of a novelty then. It may have been of course that that was just a happy circumstance, and that had I tried it again it would have been worse. I only have four strips left for it now, so it'll be retired...

Thanks for your wishes, wish you the best too.

Regards,

Will.