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Do you believe your readings?

Janiept

Expert
Messages
5,311
Today for some bizarre reason I decided to double check my BG levels, once with strips dated Dec '13 and then with strips dated May '14.

The first read 6.8 and the second 7.4. Quite frankly I am now wondering whether there is any point in testing if the readings are unreliable.

Does anybody else have this type of experience and what have you decided to do I wonder?
 
I think other people have found this ( sure I read something similar on here). I am sure for meters it is accepted that repeated results will differ slightly, although I can't remember what an acceptable difference is.

Have you got a special testing strip or solution to check your meter is functioning how it should ? (Just in case there is something wrong with it). I know mine has a special strip I put in it to tell me it is ok.

Despite this small difference it is vitally important you still test and use these reading to help you with controlling your diabetes. Otherwise (if you're like me) you won't have much of an idea of what your readings are unless you're low. Testing and doing something about the readings will stop you developing serious complications.


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We have no choice but to accept the readings. I don't however worry too much over the odd dodgy reading. Better to look for patterns/trends etc.


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I think readings are not very accurate - probably to within 1.5 ish.
I more look for trends though and take that accuracy in to account.
Try to keep below 6 always which will hopefully mean it's below the NICE guideline of 7.8. Not too concerned if it is occasionally a bit higher. If I get a reading above 8 (like yesterday) I will try to guess why and don't do that again - and exercise and no carbs until it comes down again.


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Meters are only accurate between 10% so results will always differ

Take a look at the side of your strip pot there will be a control range something like. 5.7 - 8.7

This means if you run a trst with the control solution and the result is anywhere between 5.7 & 8.7 then the result is accurate enough for home testing

But 5.7 to 8.7 is quite a gap!


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Thanks all for your replies.

Patch, I have never heard of a testing strip which sounds useful. My meter is a One Touch Ultra Easy issued by doctor do you have any idea where to get a testing strip?
 
Janiept said:
Thanks all for your replies.

Patch, I have never heard of a testing strip which sounds useful. My meter is a One Touch Ultra Easy issued by doctor do you have any idea where to get a testing strip?
Click to expand...

They come with the metres. Mine came with a strip but past ones have just come with a testing solution.
 
Most meter suppliers will send you a control solution for free, with some if you register your meter on line you can then order control solutions that way, some other freebies as well.
 
Yes, just contact lifescan (phone number is on their website) they will send you the control solution free of charge. You use it with a normal test strip, there is a guide on the side of the bottle to let you know what the result should be. There is also a way to let the meter know you are doing a control test, then it isn't stored in your results. I can't remember the sequence of buttons but it's in the instruction book.

As to whether I believe the result, well they are all I have to go on. There are times when I have retested as the result does not match how I feel, usually as a result of rushing and not washing my hands. Testing after pouring juice for the kids can lead to some "interesting" results.
 
Thanks guys, you are great. I am just off to the web site to order the control solution and hopefully my faith in meter will be restored.
 
There are a few factors that will effect the accuracy of the reading.
1) The quality of your meter
2) The Open Vial Stability (OVS) duration of strips: most strips only last for 3 months once the pot of strips has been opened for the first time and exposed to oxygen. The oxygen gradually causes the enzymes in the strips to deterioate. Some strips' OVS has only been 1 month. Good strips like the Jazz strips last 6 months once opened.
3) Were your hands clean and dry? Were you using an old lancet? Lancets should be single use

I hope this helps
 
Unfortunately test strips are not so reliable and this is a big problem if you want to keep a tight control and avoid risk of hypo.
In 33 years of diabetes I have seen so many mistakes in blood sugar readings. If you test 5 times in the same moment you will get 5 different results and unfortunately the difference can sometimes be much higher than 3. I have discussed this with doctors and they are fully aware. I have discussed this with pharma companies and they admitted this issue exists. But this is the best we have at the moment and hope in an improvement.


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Gosh Stefano that's very worrying and takes me back to wondering whether there is any point in checking especially if the difference can be so significant.

I am fortunate in that I don't have to worry about risk of hypo but for those who do - :crazy:
 
Well I've never had readings with such a big difference. I think they are accurate enough for home use. It will spot highs and lows. Look for patterns or trends, not just one-off readings.


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mo1905 said:
Well I've never had readings with such a big difference. I think they are accurate enough for home use. It will spot highs and lows. Look for patterns or trends, not just one-off readings.


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Click to expand...

I agree with this. Sure the readings differ very slightly but without doing them I would have no idea what they were at all !
 
I believe the readings that come from HbA1c's but I look at my finger tip spot blood tests as giving a good indication of my bg levels at the time taken but not a truly accurate reading.

All home testing meters have to comply with certain criteria and the tolerances that are set down are plus/minus 20% and meters will be most accurate at lower levels as the inaccuracy will have a smaller effect the lower the actual reading.

Even the same meter can give differences when testing the same blood sample with different test strips.

Home meters are an invaluable tool to show what different foods do to your bg levels so you can adjust your diet, they are also an invaluable tool to show you trends in your overall control and they will generally show you to the nearest decimal point where your bg level may be at any time but they are not 100% accurate, certainly not when it comes to tenths of units.
 
I use 2 different makes of meter and I trust both of them, they do give slightly different readings at the higher levels, at the lower levels they are very close to each other. One I use as my driving meter as its all in one the Accu Chek mobile and the at home meter the Bayer contour next usb, which has great software for doing reports.
 
The accuracy of these meter is questionable.

I tested SD Codefree vs Contour XT with the same blood sample at the same second at random times of day:

SD vs XT

9.2 vs 7.4
6.1 vs 5.4
5.8 vs 5.1
6.3 vs 4.8
6.1 vs 5.3
7.9 vs 6.5
7.7 vs 5.8
7.6 vs 6.7

The Contour always reads at least 0.7 lower.

But I can find no mathematical relationship to explain the difference. The average deviation on this very small sample is -1.2.

Some manufacturers claim as high as 98% accuracy whatever that means.

I have stopped testing for now because I generally have a good fix on my body's behaviour with six months of measurements. If my HbA1c should change critically then I will need to measure again.

It is difficult to have much confidence in the technology.
 
As a type 1, I need to rely on my readings and I'm happy with the consistency and accuracy.

If 2 separate readings are within 1 mmol/l of each other I'm usually happy.

I believe that the higher the reading is, the higher margin for error. So a reading of 13.5 on one strip may give you a 14.8 on another strip from the same spot. For me that's close enough to help me manage my levels.

If levels are lower and two readings give 3.8 and 4.3 then that's a bit more of an issue as you can be left wondering, should I treat it as a hypo or not? For me, I'd respond by treating it as a hypo but going easy on the treatment (as my levels don't rollercoaster so sharply these days). A couple of glucose tablets would usually sort me out and I'd test a bit later on and especially if any hypo signs return.

I'd say, have faith in your readings but be aware of their limitations.

If you are getting very misleading readings, (say 4.5 followed by a 6.6) check your hands are clean and if the wide variation stays the same, contact the meter manufacturer.

Ed
 
Before every reading I wash my hands with soap and water and swab the area with rubbing alcohol. I assumed everyone would do this. Concerned about infection as well as contaminating the sample.


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