Codefree glucose meter readings

lizzycat

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Hi, I'm pre diabetic and for the last few months have been working hard to loose weight and get fit in the hope of stopping it developing into type 2. I was using an accu check aviva to monitor my levels and see which foods are good and which to switch or avoid. At the start my morning readings were between 6 and 6.9 I have changed my diet to very low carb and now walk 5 days a week for 30 mins. I stopped checking my blood as the strips were expensive but then bought a Codefree and strips after seeing a link on this site. I was really expecting to see some good results and to my horror they were worse. I have been using the monitor for a month and yesterday decided to get some strips for the accu check. Today I did a test on both before breakfast and the accu check measured 5.2 and the codefree 7! My post dinner ones also vary a lot. I know meters can vary but that's a big varience. Now I'm in a quandry wondering which is correct!
 

andcol

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Can you tell us the batch number (LOT) of your pot of code free strips. Others can then tell you what they are seeing with that batch. I would also suggest you email home-health and tell them and see if Ryan comes back with other reporting it. Out of interest I have found my accucheck consistently under-reads while the codefree is a little high when compared to my HbA1c. Ok not that scientificas there are lots of sample points missing.

This is the reason why we say you are looking for trends in levels and not absolute values.
 

Bluetit1802

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All meters sold in the UK have to comply with regulations that say they must fall within a plus or minus 15% accuracy. None of them is 100% accurate. Unless you need an accurate reading in order to inject the correct units of insulin, it matters not. Worry not about the numbers, stick to one meter and keep the other locked away as a spare. Just look for trends, up or down, using that one meter.

You will always get rogue readings with any meter, maybe a faulty strip or user-error. If a reading is well out of your normal range for that time of day, test again another 2 times to confirm matters. Then if 2 of the readings are close and are within your normal range, accept it, record it, and move on. If not, average them and move on. Not much else you can do. ;)

As a PS the Codefree generally reads higher than the AccuChek Mobile. I can't speak for the Aviva.
 

Oldvatr

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Can you tell us the batch number (LOT) of your pot of code free strips. Others can then tell you what they are seeing with that batch. I would also suggest you email home-health and tell them and see if Ryan comes back with other reporting it. Out of interest I have found my accucheck consistently under-reads while the codefree is a little high when compared to my HbA1c. Ok not that scientificas there are lots of sample points missing.

This is the reason why we say you are looking for trends in levels and not absolute values.
I have this same problem with the Codefree. it reads between 1.5 mmol/L and 15 mmol/L higher than my Abbott Neo. The high readings I ignore as misreads. They occur about once a fornight, even off the same blood sample. The SD Codefree is calibrated for Plasma, which means ir will always read high by a factor of 1.12 (i.e. 12%) just on calibration alone. Note other new meters (2012 on) are also calibrated for Plasma, such as most recent Accuchek meters, but older meters and it appears at least most Abbott are still calibrated in the old Whole Blood system. Not sure what other meters follow - check with manufacturer

Add to this the fact that two meters sampling the same blood drop are permitted to differ by up to +/- 20% and still be considered 'acurate'. Thus if the actual bgl drop is 10 mmol/l, then one meter could say 8mmol/l and the other say 12 mmol/l and both would be correct. Next yearI*) new meters will need to meet a tighter accuracy ~(+/- 15% each)
EDIT(*) From Mqy 2016.
 
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Oldvatr

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All meters sold in the UK have to comply with regulations that say they must fall within a plus or minus 15% accuracy. None of them is 100% accurate. Unless you need an accurate reading in order to inject the correct units of insulin, it matters not. Worry not about the numbers, stick to one meter and keep the other locked away as a spare. Just look for trends, up or down, using that one meter.

You will always get rogue readings with any meter, maybe a faulty strip or user-error. If a reading is well out of your normal range for that time of day, test again another 2 times to confirm matters. Then if 2 of the readings are close and are within your normal range, accept it, record it, and move on. If not, average them and move on. Not much else you can do. ;)

As a PS the Codefree generally reads higher than the AccuChek Mobile. I can't speak for the Aviva.
The new limits come later on this year. Don't think a date has been set, but it is not New Yr Day. You can still get old stock meters 'as new' and no one will be able to confirm which standard they are meeting except the manufacturer with the meter serial number.
EDIT: In 2013, an updated set of standards (ISO: 15197:2013) were published and these newer standards will need to be met blood glucose meter manufacturers by the end of May 2016.
The new limits will be
.Within
± 0.83 mmol/L of laboratory results at concentrations of under 5.6 mmol/L
(Within ± 15 mg/dl of laboratory results at concentrations of under 100 mg/dL)

Within ± 20% of laboratory results at concentrations of 5.6 mmol/L (100 mg/dL) or more

NOTE: The limit remains 20%, not 15% as stated previously.
ERROR: @Administrator The above info was copied from DCUK website. It is wrong. the correct values taken from the ISO itself are:
  • Increased accuracy for glucose meter systems, in particular for glucose values greater than 75 mg/dl (4,2 mmol/l)
  • Manufacturers of glucose meter systems must ensure their technology enables accuracy to improve from +-20% to +-15%
  • The new version accounts for 99% of results, as opposed to 95% for the previous one
  • For the first time, the standard provides formal acceptance criteria for accuracy as regards testing by patients and assessment of interferents (including hematocrit).
 
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andcol

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the codefree is already at +-15%
 

Oldvatr

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The manufaturer of the SD claims this, but it does not appear to have been independently verified. Mine certainly does not meet the new standard on a reading by reading but does meet 20% limit when averaged over a fortnight. I drew a graph onceof the errors as a percenage of reading, and it looked like someone had fired a shotgun at the page. The error was all over the place, but the line of best fit was correct. This is a new meter purchased Sep 2015. My NEO was purchased Aug 2015. Both meters when averaged over several months were within 1 mmol/L of my HBA1c plasma equivalent.
 

Bluetit1802

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The manufaturer of the SD claims this, but it does not appear to have been independently verified. Mine certainly does not meet the new standard on a reading by reading but does meet 20% limit when averaged over a fortnight. I drew a graph onceof the errors as a percenage of reading, and it looked like someone had fired a shotgun at the page. The error was all over the place, but the line of best fit was correct. This is a new meter purchased Sep 2015. My NEO was purchased Aug 2015. Both meters when averaged over several months were within 1 mmol/L of my HBA1c plasma equivalent.

Out of interest, how do you know your Codefree does not meet the new standard but does meet the 20% standard when averaged over a fortnight? What are you comparing it with? Do you have a 100% accurate way of checking it? You cannot under any circumstances compare any finger pricking meter with an HbA1c. It simply does not work unless you finger prick every 10 minutes 24/7 and discount the fact you may be a high or low glycator.
 

Oldvatr

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Out of interest, how do you know your Codefree does not meet the new standard but does meet the 20% standard when averaged over a fortnight? What are you comparing it with? Do you have a 100% accurate way of checking it? You cannot under any circumstances compare any finger pricking meter with an HbA1c. It simply does not work unless you finger prick every 10 minutes 24/7 and discount the fact you may be a high or low glycator.
My two meters track each other for averaged values within +/- 2 mmol/L Day to day they can differ by up to 8 mmol/L on a repeated reading. I take both meters with me when i see the vampire, then I compare the result from the lab on the blood taken at the same time.
Actually I find that HBA1c vs meter to be quite steady and within 1 mmol/L. The SD reads 1 mmol high, the NEO 1 mmol low, which is what the average readings at that time show. There is no way one can verify calibration because the so called solutions do not specify their titrated value. My NEO also tracked both my XCEEDs very well, much better than the SD, so i know the SD is not reliable. The reason why I suspect theSD of not reading to 15% is that i get errors of 4 or 5 mmol/L between the meters so one or both is outside the 15% Since the NEO is more consistent, i tend to give it the doubt. It is not very comforting when I get the symptoms of a hypo, and the NEO reads 3.7, and the SD reads 6.4. i know which one I trust more.
 

andcol

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I think you either have a faulty SD meter or a bad set of strips because I have only ever seen this erratic behaviour on the SD with one batch which I tested about a thousand strips for Home-Health on 2 different meters at varying glucose levels.That batch was definitely erratic but there was little variance between meters.
 

Oldvatr

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I think you either have a faulty SD meter or a bad set of strips because I have only ever seen this erratic behaviour on the SD with one batch which I tested about a thousand strips for Home-Health on 2 different meters at varying glucose levels.That batch was definitely erratic but there was little variance between meters.
The SD passes the calibration test using the solutions, and so Home Health would not change the meter. Last night I had low readings.The NEO registered 4.7, the SD read 7.2. i may have a faulty meter, but what worries me is that if i was not parllel comparing, then i would not be aware of it, and would have treated my 7.2 reading last night as being fine to drive. it ticks the DVLA box.

Without the NEo to compare with i would have gone to sleep happy, and possibly gone into hypo overnight. If I woke and tested, i might have had a reading on the SD of say 4.5. and assumed that although low, it was not close to hypo, but I may well be around 3.5 and in danger of losing it.

But the SD passes the calibration test.

The calibration fluid should be a titrated solution with a verifiable value that we can use as a primary reference, not a general ball park range that is too vague. You can drive a coach and horses through the process.
 

lizzycat

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Can you tell us the batch number (LOT) of your pot of code free strips. Others can then tell you what they are seeing with that batch. I would also suggest you email home-health and tell them and see if Ryan comes back with other reporting it. Out of interest I have found my accucheck consistently under-reads while the codefree is a little high when compared to my HbA1c. Ok not that scientificas there are lots of sample points missing.

This is the reason why we say you are looking for trends in levels and not absolute values.
Hi Andrew thanks, the lot no is S0315037 just checked and reading on codefree is 6.2 and 5 on the accu check. I guess the best thing will be to wait until my next HbA1c and see if all my effort has reduced it.
 

Bluetit1802

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Hi Andrew thanks, the lot no is S0315037 just checked and reading on codefree is 6.2 and 5 on the accu check. I guess the best thing will be to wait until my next HbA1c and see if all my effort has reduced it.

I have been using that batch ending 37 since October. I find it consistent (other than the usual rogue readings we all get) and fine for spotting trends, up or down, and helping with dietary tweaks. I have done cross checks with my AccuChek Mobile. The AC does read a tad lower, but nothing significant when averaged over a period. Unless you rely on meter readings to inject the correct amount of insulin or swallow glucose tablets, the actual numbers do not matter. You really can't anticipate your HbA1c from the readings unless you test every 10 minutes 24/7. Just look for trends.
 

Oldvatr

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I have been using that batch ending 37 since October. I find it consistent (other than the usual rogue readings we all get) and fine for spotting trends, up or down, and helping with dietary tweaks. I have done cross checks with my AccuChek Mobile. The AC does read a tad lower, but nothing significant when averaged over a period. Unless you rely on meter readings to inject the correct amount of insulin or swallow glucose tablets, the actual numbers do not matter. You really can't anticipate your HbA1c from the readings unless you test every 10 minutes 24/7. Just look for trends.
I am sorry but I disagree. i drive so I need to know with confidence what my levels are before and during this activity. When i have my NEO reading 3.7 with hypo aware warnings starting, but my SD tells me i am at 6.4 as happened the other day, then I have to take action and deal with it. If i only had the SD, then I would probably wrongly interpret my actual condition until it became so severe I needed the medics. As I have stated, I cannot trust my SD in the area I need it, i.e when running bgl near hypo range. If both meters are meeting the older ISO standard, then I should be seeing WORST CASE only 1.6 mmol difference at <5.6 and that assumes that the NEO is reading low, and the SD is reading high and also both are at the limit of accuracy, In the instance the other day I had a difference of 2.8. so at least one is not meeting spec.

PS I am using the same batch as above.
 

Bluetit1802

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I am sorry but I disagree. i drive so I need to know with confidence what my levels are before and during this activity. When i have my NEO reading 3.7 with hypo aware warnings starting, but my SD tells me i am at 6.4 as happened the other day, then I have to take action and deal with it. If i only had the SD, then I would probably wrongly interpret my actual condition until it became so severe I needed the medics. As I have stated, I cannot trust my SD in the area I need it, i.e when running bgl near hypo range. If both meters are meeting the older ISO standard, then I should be seeing WORST CASE only 1.6 mmol difference at <5.6 and that assumes that the NEO is reading low, and the SD is reading high and also both are at the limit of accuracy, In the instance the other day I had a difference of 2.8. so at least one is not meeting spec.

PS I am using the same batch as above.

Actually, I was replying to @lizzycat who is not medicated and therefore not going to drop into hypoland, and I did say numbers matter for injecting insulin or swallowing glucose tablets. As you fall into this group (on Gliclazide) numbers do matter for you and I understand that. They do not matter for Lizzycat to the extent that she needs to stress over meter inaccuracies. What she needs to do is put one of her meters away and stick to the other, watching for trends, and how quickly she rises and falls so she can tweak her diet. Stressing over the differences between 2 or more meters will not help her.
 
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Pinkorchid

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I often wonder because the Codefree strips are so much cheaper than others if they are quite as reliable...allowing for the 20%... as other more expensive strips. Does anyone know the reason why the Codefree strips are so much cheaper and not just a little but a lot cheaper and from what people say they tend to read higher than the more expensive ones
 

Oldvatr

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I often wonder because the Codefree strips are so much cheaper than others if they are quite as reliable...allowing for the 20%... as other more expensive strips. Does anyone know the reason why the Codefree strips are so much cheaper and not just a little but a lot cheaper and from what people say they tend to read higher than the more expensive ones
I have not seen a single posting in this forum where someone has reported the SD Codefree reading lower. Not one, though I stand to be corrected. The problem with the ISO requirement is that the meter has to be designed to meet the requirement. Once this has been verified, then it is licenced, and there is no further requirement for the production line to validate each meter. A meter manufacturer only has to demonstrate that the design CAN meet ISO, not that every meter DOES. This is maybe why the calibration fluids are so wishy washy. they only need to detect faulty meters that are grossly malfunctioning.

I have noted that my SD and my NEO have differed by more than 30% of reading, but not the 40% that the okder ISO standard required. Since the new iSO (i.e. 15%) is not yet in place, then i have to say that my meters are reading correctly and that neither is faulty. This is why i cannot get mine replaced.

I try to use trends to base my decisions on, and use averages wherever I can. The one area I cannot do this is when checking for hypo and safety to drive or operate machinery. i use 2 meters, and take the lower reading for this check, and the other meter then provides a sanity check.
 

Brunneria

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Actually, I was replying to @lizzycat who is not medicated and therefore not going to drop into hypoland, and I did say numbers matter for injecting insulin or swallowing glucose tablets. As you fall into this group (on Gliclazide) numbers do matter for you and I understand that. They do not matter for Lizzycat to the extent that she needs to stress over meter inaccuracies. What she needs to do is put one of her meters away and stick to the other, watching for trends, and how quickly she rises and falls so she can tweak her diet. Stressing over the differences between 2 or more meters will not help her.

Absolutely.

@Oldvatr I recognise tht this is an issue for you, but I have to say I am not sure your comments are appropriate for a newbie thread where @lizzycat is pre-diabetic, learning to manage her diet and is not medicated.

Your situation and your meter needs are so different that I cannot help but think you are muddying the waters for her.
 

AndBreathe

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I have not seen a single posting in this forum where someone has reported the SD Codefree reading lower. Not one, though I stand to be corrected. The problem with the ISO requirement is that the meter has to be designed to meet the requirement. Once this has been verified, then it is licenced, and there is no further requirement for the production line to validate each meter. A meter manufacturer only has to demonstrate that the design CAN meet ISO, not that every meter DOES. This is maybe why the calibration fluids are so wishy washy. they only need to detect faulty meters that are grossly malfunctioning.

I have noted that my SD and my NEO have differed by more than 30% of reading, but not the 40% that the okder ISO standard required. Since the new iSO (i.e. 15%) is not yet in place, then i have to say that my meters are reading correctly and that neither is faulty. This is why i cannot get mine replaced.

I try to use trends to base my decisions on, and use averages wherever I can. The one area I cannot do this is when checking for hypo and safety to drive or operate machinery. i use 2 meters, and take the lower reading for this check, and the other meter then provides a sanity check.

Are you still taking Gliclazide? If so, why are your strips not on prescription, if you are taking potentially hypo inducing medication?

If you are, then I think your solution is to sort out your prescription requirements, and if you're no longer on this class of medication your requirements for driving will have significantly softened.

Aside from the earliest days, before I learned of the Codefree, I have been a Codefree user. Sure, I've experienced some odd readings, and did have issues with the batch Andrew mentions, but the supplier replaced those strips, as a gesture of goodwill, as so many experienced the issue. For me, I'm looking at peaks, troughs and trends. The absolute numbers are not so important.

Personally, my stats illustrated that I haven't fared too badly on the Codefree and I would suggest many, many others are in the same boat. If you are going to be caught up in the minutiae of all of this, you'll lose your sanity and perspective needlessly. Diabetes, if it wants to hang around, needs to hang around on my terms. I'm not intending to be governed by the minutiae of it.
 
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Oldvatr

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Absolutely.

@Oldvatr I recognise tht this is an issue for you, but I have to say I am not sure your comments are appropriate for a newbie thread where @lizzycat is pre-diabetic, learning to manage her diet and is not medicated.

Your situation and your meter needs are so different that I cannot help but think you are muddying the waters for her.
The OP posted <<I know meters can vary but that's a big varience. Now I'm in a quandry wondering which is correct!>> i was replying to this question. I have not gone off topic. But I take your point and will not post again.