SD Codefree giving high readings?

I too have just changed to the SD for financial reasons.

When I compared to my Freestyle lite the SD did show a point or two above but I am not too bothered as it will show me of any rises and I think that's more important than the actual number. Hope this makes sense.

CatAndLucy said:

I recently bought this monitor to replace a Freestyle Optimum Neo I was given when pregnant (about 2 years ago) with GD but can't afford to run.
I've been getting really pleasing readings from the freestyle, (between 4.9 and 6.2) but since I started using the SD I've been 6+. I've just done a comparison test with both and the Freestyle reads 5.5 and the SD reads 6.6.
Do SD Codefree often read high?

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I hope you find the new meter to your benefit. I asked Google Medical Research if they could manufacture a watch attached to the skin and giving a frequent blood sugar dial. Wouldn't that be great? I suppose infection may be a risk. I don't know how a blood sugar measurement could be made otherwise.
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@Serena51

One thing to consider is that the Codefree is designed to internally convert the whole blood reading from the finger prick to a plasma reading, bringing it in line with the venous tests of plasma blood we see when we have our HbA1c tests.

Older meters may not have this conversion built in.

Whole blood tests (finger pricks) are typically approximately 12 per cent lower than plasma tests (venous) because the glucose content of whole blood is usually lower than the glucose content of plasma. Therefore meters calibrated to do this conversion may read 12% higher than other meters.

You should be able to find if your old meter is calibrated that way by reading the original leaflets that came with it.

I have two meters and CodeFree is typically 1.0-1.5 mmol higher for the same test

Just be aware and adjust mentally


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KevinPotts said:

I have two meters and CodeFree is typically 1.0-1.5 mmol higher for the same test

Just be aware and adjust mentally


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Kevin, do you find this with every tub of Codefree from all batches, or just certain tubs from different batch numbers?
I find some tubs/some batch numbers read virtually the same as my Accu Chek Mobile, whilst others differ.

Thanks for your thoughtful reply Bluetit.

CatAndLucy said:

Do SD Codefree often read high?

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Mine does and always has by about the same amount as yours. In the higher ranges it goes into orbit. I did some comparison tests using control solution a couple of years ago. I got results like yours in the lower ranges but a solution that should have read 16.7 read 23.5 in the higher range. I never go that high so I am not fussed. I am only concerned that I don't mislead DN who thinks that I am using an Abbott freestyle. To this end I knock one mmol off the reading if I am keeping records.

Bluetit1802 said:

@Serena51

One thing to consider is that the Codefree is designed to internally convert the whole blood reading from the finger prick to a plasma reading, bringing it in line with the venous tests of plasma blood we see when we have our HbA1c tests.

Older meters may not have this conversion built in.

Whole blood tests (finger pricks) are typically approximately 12 per cent lower than plasma tests (venous) because the glucose content of whole blood is usually lower than the glucose content of plasma. Therefore meters calibrated to do this conversion may read 12% higher than other meters.

You should be able to find if your old meter is calibrated that way by reading the original leaflets that came with it.

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Oh crikey. I'm really running my bs too low then!
But does this also mean that your average displayed on Code Free is likely to be closer to your Hb than the average on other meters?

RuthW said:

Oh crikey. I'm really running my bs too low then!
But does this also mean that your average displayed on Code Free is likely to be closer to your Hb than the average on other meters?

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That is the intention, but it all depends how many times, and when, you test. You have to catch the peaks, not just a 2 hour reading. I imagine most meters now are calibrated to do this internal calculation. It will say somewhere in your meter leaflets, or even on-line. It is easy to find for the Codefree, not so easy for the Accu Chek as it is buried in the middle of the technical specifications that no-one ever reads! Have a read through your meter manual, or look at their website. It may say something like "plasma calibrated"

Bluetit1802 said:

That is the intention, but it all depends how many times, and when, you test. You have to catch the peaks, not just a 2 hour reading. I imagine most meters now are calibrated to do this internal calculation. It will say somewhere in your meter leaflets, or even on-line. It is easy to find for the Codefree, not so easy for the Accu Chek as it is buried in the middle of the technical specifications that no-one ever reads! Have a read through your meter manual, or look at their website. It may say something like "plasma calibrated"

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I test a lot. before and after every meal and at other random times!

RuthW said:

I test a lot. before and after every meal and at other random times!

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So do I. I test before and twice after, sometimes more than twice. Yet my averages never align with my HbA1c. My HbA1c is always higher than I am expecting. Sad.

I read things like this and get more confused about my numbers ... I still have lots to learn - @Bluetit1802 you are such a wonderful person to have in this forum, I learn so much from your posts - thank you

PenfoldAPD said:

I read things like this and get more confused about my numbers ... I still have lots to learn - @Bluetit1802 you are such a wonderful person to have in this forum, I learn so much from your posts - thank you

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What a lovely and kind thing to say. I'm blushing. Thank you. I also have a lot more to learn, and the more I do learn the more mysterious and confusing it all becomes.

You are doing fantastically well, despite any confusion!

So tonight I'm 5.1, which could be 4.1 ... but actually I'm not worried - it's a good reading I'm going to sleep happy, I was a good boy and didn't eat any chocolate while watching Absolutely Fabulous - especially hard given the lame movie

PenfoldAPD said:

So tonight I'm 5.1, which could be 4.1 ... but actually I'm not worried - it's a good reading I'm going to sleep happy, I was a good boy and didn't eat any chocolate while watching Absolutely Fabulous - especially hard given the lame movie

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This is the serious issue with meters like the SD. If you were reading in the 4's then you might actually be in the 3's. Below 4 on a whole blood meter is rated as hypoland. It's as well that people know this.

Surely what it reads is what it reads, for T2? OK, there have been the odd glitch where a batch of strips have been a bit "odd", but what is anyone actually going to do, on a day to day basis if you're meter says 4.9 and venous blood would have you at 4.5 or 4.9, or whatever?

I can see that it could be more important for T1s, or those taking potentially hypo inducing medication, but those individuals should having their meters and strips prescribed, which is very unlikely to be the Codefree.

My Codefree meter readings, when converted, using the usual converter tools, such as on this site, are never that close to the venous tests the lab analyses. That said, nor are the venous tests close to my Libre averages, which are usually lower than my Codefree readings.

When I swap from one batch (as opposed to each pot) to another, I usually do 2 or 3 comparative tests, then I just go with the flow, but then I'm really concentrating on my trends and my return to baseline times.

Maybe I just over simplify things, but it works for me.

Bluetit1802 said:

Kevin, do you find this with every tub of Codefree from all batches, or just certain tubs from different batch numbers?
I find some tubs/some batch numbers read virtually the same as my Accu Chek Mobile, whilst others differ.

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My NEO reads low compared to my SD Codefree, and has only once ever read higher (due to misread) Batches seem to be consistent once opened, but there is definitely batch to batch variation of up to 1 mmol/l when comparing average values over the month or so that my pak lasts me. Remember that when comparing two meters side by side, that each can have a batch variation when starting a new pak. so I have nonths when this occurs twice in succession.

I keep a spreadsheet that is set up to automatically calculate the differences for each reading I log, and then I keep a running average to show what adjustment is necessary. It only really becomes a problem when I run out of strips for one meter, and have to rely on the other to base my decisions on (such as DVLA checks, hypo checks Hypo recovery retests etc).

As an aside, my last 3 HbA1c results actually landed almost exactly midway between the averages of both meters on the day the bloods were drawn, so I have reasonable confidence in predicting what my next result will be.

BTW the Accucheck and SD Codefree meters have the same method of calibration nowadays (Plasma) so should read very similar, whereas Abbott and other makes may still be whole blood. My older Xceeds both read whole blood like my NEO and read lower than the SD.

AndBreathe said:

My Codefree meter readings, when converted, using the usual converter tools, such as on this site, are never that close to the venous tests the lab analyses. That said, nor are the venous tests close to my Libre averages, which are usually lower than my Codefree readings..

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According to the info in that converter tool you refer to, if your meter is calibrated to convert to plasma, there is no need to do any conversion. The Codefree is calibrated to be "plasma equivalent" .

Bluetit1802 said:

That is the intention, but it all depends how many times, and when, you test. You have to catch the peaks, not just a 2 hour reading. I imagine most meters now are calibrated to do this internal calculation. It will say somewhere in your meter leaflets, or even on-line. It is easy to find for the Codefree, not so easy for the Accu Chek as it is buried in the middle of the technical specifications that no-one ever reads! Have a read through your meter manual, or look at their website. It may say something like "plasma calibrated"

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The SD is hard calibrated in the meter itself, but Accuchek changed their strips to make the transition to plasma 'truly codefree' so it will not be in the Accuchek leaflet for the meter. Their website confirms this strip change since 2011. No changes to meter hardware was required.