Very different readings from 2 meters

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I've been using a Nexus GlucoRX for the past 9 months and it seems to have been accurate - 5.1/5.2 fasting, down to 7 postprandial readings, lowest has been 4.0. But to save money, I've swtiched to the SD codefree yesterday, and found that the readings are about 10-15% higher on that, I've still got some GlucoRX strips left, so been testing the same blood with both and got, for instance: 5.2 (GlucoRX) and 5.9 (SD) this morning. At lunchtime after a gym visit before food I got 6 and 6.9.

I knew they weren't hugely accurate, but online a figure of 10-15% is quoted - these are practically dead on 15% different. I've read suggestions that you can get a lab BG test to calibrate - but I wouldn't know where to start - this sounds a bit theoretically true, but not actually practical to me.

Anyone else found the CodeFree to be so highly over, or the GlucoRX to be highly under, or both?
 
It's maths, really. If you have one device that reads 10% low, and another that reads 10% high, then the added difference seems very high, but it may not be.
You have no idea which one is more accurate, and the only way to do that is to record the BG from a test strip at the same time a venous sample is being taken. There will be a difference. That difference may crush your faith in fingerpricks altogether, of course.😉
 
I quite agree, novorapid. It doesn't really matter which device you use.
 
ChrisSamsDad said:
I've been using a Nexus GlucoRX for the past 9 months and it seems to have been accurate - 5.1/5.2 fasting, down to 7 postprandial readings, lowest has been 4.0. But to save money, I've swtiched to the SD codefree yesterday, and found that the readings are about 10-15% higher on that, I've still got some GlucoRX strips left, so been testing the same blood with both and got, for instance: 5.2 (GlucoRX) and 5.9 (SD) this morning. At lunchtime after a gym visit before food I got 6 and 6.9.

I knew they weren't hugely accurate, but online a figure of 10-15% is quoted - these are practically dead on 15% different. I've read suggestions that you can get a lab BG test to calibrate - but I wouldn't know where to start - this sounds a bit theoretically true, but not actually practical to me.

Anyone else found the CodeFree to be so highly over, or the GlucoRX to be highly under, or both?
Click to expand...
I wouldn't be at all surprised if I saw a 5.2 and a 5.9 from the same meter let alone two different ones!
 
I'm going to test my meter on Thursday morning Mikey.

I'm going to have bloods taken for my annual D check at my GPs and for some reason best known to our CCG not only do they do the HbA1c - they also lab test your BG ! so I'll have my meter loaded and ready to grab some out of the hole on my arm as she removes the needle before she staunches the flow. If I happen to get a bruise it's hardly the end of the world.

And I'll know the answer next week!
 
I have a Codefree & a Contour Next USB. The Contour is always 1 mmol/l higher than the Codefree. So in my situation, i'm the reverse to you @ChrisSamsDad .
 
I am reading this because I too am confused. I have been T2 for several years but recently have been doing a low carb exercise which requires me to record my food and levels. I have tried two new meters, a Nexus and an Accucheck mobile (which contains integral automatic strip system). previously I used one touch verio. I have used control solution on the one touch verio and the Nexus and they are within their guidelines however the readings vary so much that I do not feel I am keeping accurate levels. when I rang one touch they simply said I should not compare meters!!
today I tried all three at the same time and got - on touch verio 5.2.......Nexus 4.........Accuchek 3.9 so I have no idea which most represents my situation.
 
You will probably find you get different readings using one meter on the same drop of blood. There is a 15% tolerance.
 
Although there is supposed to be a tolerance of 15% it does decrease as you reduce and get more accurate as your BG lowers to 4. for most of us the important values are close to 4 and if you are hypo aware then you should know without your meter. If you are hypo and your meter reads 6 then there is something wrong with the meter.
Rubyrose with your three readings, were you hypo? 2 meters said you were, if not then the one-touch verio is probably the most accurate. You can however get similar variations with the same meter (3 separate finger pricks? or all from the same finger prick). You can get false readings my squeezing too hard on your finger.
Stick to your favorite meter.
 
Vicsetter said:
Although there is supposed to be a tolerance of 15% it does decrease as you reduce and get more accurate as your BG lowers to 4. for most of us the important values are close to 4 and if you are hypo aware then you should know without your meter. If you are hypo and your meter reads 6 then there is something wrong with the meter.
Rubyrose with your three readings, were you hypo? 2 meters said you were, if not then the one-touch verio is probably the most accurate. You can however get similar variations with the same meter (3 separate finger pricks? or all from the same finger prick). You can get false readings my squeezing too hard on your finger.
Stick to your favorite meter.
Click to expand...
Vicsetter said:
Although there is supposed to be a tolerance of 15% it does decrease as you reduce and get more accurate as your BG lowers to 4. for most of us the important values are close to 4 and if you are hypo aware then you should know without your meter. If you are hypo and your meter reads 6 then there is something wrong with the meter.
Rubyrose with your three readings, were you hypo? 2 meters said you were, if not then the one-touch verio is probably the most accurate. You can however get similar variations with the same meter (3 separate finger pricks? or all from the same finger prick). You can get false readings my squeezing too hard on your finger.
Stick to your favorite meter.
Click to expand...
Vicsetter said:
Although there is supposed to be a tolerance of 15% it does decrease as you reduce and get more accurate as your BG lowers to 4. for most of us the important values are close to 4 and if you are hypo aware then you should know without your meter. If you are hypo and your meter reads 6 then there is something wrong with the meter.
Rubyrose with your three readings, were you hypo? 2 meters said you were, if not then the one-touch verio is probably the most accurate. You can however get similar variations with the same meter (3 separate finger pricks? or all from the same finger prick). You can get false readings my squeezing too hard on your finger.
Stick to your favorite meter.
Click to expand...
hi vicsetter, thank you for your reply. no, I was not hypo and I never have been hypo since diagnosed although according the one touch verio, which gives the highest readings, I have had levels in the past of 4 and 4 plus. I am on Eucreas (metformin) 50mg/850 one twice daily. I used new needle each time (using the accu-chek multi clix). I did not need to squeeze blood out. these meters always differ in readings and I understand it is not that critical but I would like to know which is most accurate.
I am with a group for 16 weeks eating low carb, although I know I will not take it as low as some there but it is a regime I was recommended to six years ago when diagnosed in spain and it worked well for me on the whole. on returning to uk my diabetes nurse has no truck with this, wants me to eat potatoes, rice, bread, pasta etc but also tells me it is inevitable that I will end up on insulin which I found a very depressing point of view.
 
I'll tell you what I think - the accu-chek and the nexus are correct. Why?

Going back to before I had my first pump I had a One-Touch meter. Loved it. Not a Verio, can't recall the name now. Oddly though, my A1c was always slightly higher than my meter readings indicated. I discounted that, after all, all meter readings only ever represent odd seconds of your life, whereas the A1c test indicates everything that occurs in between. So I swapped to my pump and with that, I got the matching Accu-Chek Expert meter which also acted as a remote control for the meter, so although the remote could be useful for the latter - I absolutely HATED the thing because it invariably read HIGHER than my trusty One-Touch - which I continued to use, because I trusted it. Then I had my next A1c - and though I'd absolutely counted every single gram of carb I ate and calculated the insulin equally exactly and tested tested tested - I was like a robot - my whole life was managing my diabetes and no deviation for that time - my A1c hadn't altered one little bit despite that diligence. Still higher than my meter indicated. I felt like shooting myself .... whatever I do I can't get my A1c down.

I hated that. And only then - I flippin realised. The Accu-chek readings were the correct ones - when the One Touch said I was 4 - I was really 5+, when it said I was 10 - I was nearer 12 ......... so I swapped to the Accu-Chek, wasn't at all as dedicated at recording every gram, just 'near as dammit' estimating and having the amounts of insulin my meter told me to - and 3 months later - Bingo - my A1c was now lower than it had ever been in my life. With next to no extra effort on my part.

I am aware that this could ONLY be me. But am simply telling you what I THINK.
 
PS your UK DSN could do with nipping off to Spain and getting herself re-educated !! It is most certainly NOT inevitable - however if people follow her advice, then it most likely will be for them - so follow your own path not hers - and just say non committal things in the right places next time you have to see her!
 
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I agree with Jenny regarding your nurse's advice! I may have only been diagnosed three weeks ago but intensive daily research has made it clear to me that Type 2 CAN be reversed by a strict low-carb no-sugar diet and exercise (I say 'can' not necessarily 'will be')...

It's amazing that she could advise you to eat all those undesirable carbs! I've been quite shocked by the incredibly variable level of care people are getting, even just here in the UK.
 
The diabetes symptoms can also be reversed by a not so low carb diet and higher exercise regime.

When I improved, I was on between 150-200g of carb a day. So, it is horses for courses. Whatever demonstrably works for each of us is good! 🙂

Regarding meters, just use one when trying to improve or just monitor the diabetes. If you have to change meters then just accept the new readings and react accordingly. I changed from a Bayer Contour to an SD Codefree and did not even attempt to compare the two. The readings they give are simply not necessarily comparable.

Well, they are, but you'd have to take numerous readings on both machines (maybe over multiples of ten each) to exclude the levels of error involved (can you tell that I did a pure and applied physics degree when I was a young chap?!!)

Andy 🙂
 
I had been commenting on an earlier thread on the subject of blood test meters and was on my way back there to add an update when I came across this one. I used to use a Freestyle meter which I was quite happy with but my local surgery has now supplied me with a Nexus one. Testing is less important to me now that I am on diet and exercise only, I am only testing once a week or so, just to make sure I'm OK. It was a while before I noticed that my readings seemed to be a little bit higher than they used to be and so I suspected that the meters might be reading differently. I bought some new test strips for the Freestyle meter and started testing with both meters side by side. I have now done this on five tests and the results are:

Freestyle/Nexus (6.3/7.9) (4.7/6.6) (6.5/5.2) (7.3/7.0) (5.6/10.2)

The first two tests seemed to confirm my suspicion that the Nexus was reading higher but then the next two went in the opposite direction. The last reading was so far out that I repeated the test with the Nexus and got a second reading of 6.0 which suggests that the first was a false reading. Before I started doing the dual tests, there have been a number of times that the Nexus has given a reading that was over ten at a time when I really wouldn't have expected it to be, I now suspect that these might have been false readings too. In the case of the most recent one I had started the day with a bowl of porridge, with 100g oats and a small squirt of honey. I had then gone off and done the 5k parkrun followed by a 3.8k swim. To then get a reading of 10.2 would have been surprising had I not had the Freestyle meter to compare with.
 
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