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Are Home Testing Meters Incorrect?

Discussion in 'Ask A Question' started by neithskye, Oct 6, 2018.

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  1. neithskye

    neithskye Type 2 · Well-Known Member

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    I had my three-month-since-diagnosis blood test this week. My BG was 16.2 mmol at diagnosis on July 6th.

    When I self-tested before I left for the appointment my BG was 5.4. When I got home my BG was 4.8.

    My lab results said 7.3.

    Are home meters wrong? Does running around driving to the doctor's raise BG?
     
  2. NoCrbs4Me

    NoCrbs4Me I reversed my Type 2 · Well-Known Member

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    I think the protocol for comparing a lab test to your personal meter results is to get a reading from your personal meter at the same time as when you get the lab blood sample taken.

    Going to the doctor could raise your stress level, which could raise your blood glucose level.

    Also, is it possible the lab numbers are HbA1c results?
     
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  3. urbanracer

    urbanracer Type 1 · Moderator
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    Might do. Depends how often you shouted at the idiot on the bike in front of you who didn't indicate and whether you got stressed because your doctor's electronic sign in system failed to recognise you (again).
     
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  4. Dixon1995

    Dixon1995 Type 1 · Well-Known Member

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    Blood glucose meters at home can be 15% swing out either way, so if it was 5.4, it could explain why it was 4.8 as home, not sure about the higher reading

    Also a bit off topic as your meter seems fine, but if your ever in doubt about your blood readings, test your meter every now and then with control.

    Pic for attention, every blood checker company has their own brand of control

    [​IMG]
     
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  5. Raygower

    Raygower Type 2 · Active Member

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    Your meter is working as well as one can expect. A 0.6 variance is well within reasonable expectations given a couple of hours gap, and stable conditions i.e. no meals or marathons.

    Whether it is accurate is another question.
    You don't say whether the 7.3 was your latest A1C (no comparison), another prick test (who says their's is better than yours?), or vein sample in an analyzer.
    The simple answer is probably not.

    Different meters use slightly different methods to get a result. Those methods seem to suit some people better than others. I know a Trividia consistently gives me results 20% below anything else, but it is not the case with a colleague, for whom the errant one is my Tee2 at 20% above. We both sort of agree with a Contour Next or an Abbott Jazz (borrowed from my friendly chemist).
     
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  6. HSSS

    HSSS Type 2 (in remission!) · Well-Known Member

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    If your lab result was hb1ac it’s an average over approximately 3mths and can only really be compared to another hb1ac.

    Your readings were at that one specific point in time. They probably don’t catch every high, any liver dumps or any dawn phenomenon that push an average up. Rigorously testing every day throughout the day and seeing what your meter gives as an average might be closer. Personally i look for a downward trend in my fingerpricks overall and also to test new foods.

    If it was a finger prick instant test whose to say which meter is more accurate. Even if it was a fasting glucose test it’s still just a point in time so see above.
     
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  7. neithskye

    neithskye Type 2 · Well-Known Member

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    No. My HbA1c result was 6.1. Not great but better than the 11 it was.

    I didn't know I was supposed to bring my meter.
     
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  8. neithskye

    neithskye Type 2 · Well-Known Member

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    It's like you were there. :p
     
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  9. neithskye

    neithskye Type 2 · Well-Known Member

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    My A1C was 6.1. It was a blood test with blood drawn from my arm.

    I just find it odd that I self-tested at 5.4, had the lab test at 7.3, then self-tested an hour later at 4.8. I've been consistently in the 4-5 range for the past few weeks.
     
  10. neithskye

    neithskye Type 2 · Well-Known Member

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    My A1C was 6.1. At diagnosis on July 6th it was 11. It was a blood test from my arm.

    I self-test daily. I've been consistently in the 4-5 mmol range for the past few weeks. That's why seeing a 7.3 reading, especially sandwiched between a 5.4 and a 4.6 reading, is confusing.
     
  11. HSSS

    HSSS Type 2 (in remission!) · Well-Known Member

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    My last hb1ac was 44 which I think is about 6.2%.

    I rarely see 4 and even 5 isn’t the most frequent. I’m still thinking you are missing some higher numbers which is why hb1ac and your daily readings don’t match up.

    As for why your daily readings on the day of the lab test and their test seem at odds I’m a little lost other than natural variance. Timing of tests. Going up on the way to dr, fallen by the time you got home maybe.

    Didn’t realise anywhere used mmol for glucose and % for hb1ac. Isn’t that like mixing imperial and metric ?
     
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  12. Raygower

    Raygower Type 2 · Active Member

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    Ah. I see the confusion!
    It all comes from banding around numbers interchangably and without explaining what they are. Particularly A1C results which are expressed in several different and unrelated ways!

    An A1C response of 6.1% (or 43M/Mol) equates to an average blood sugar of about 7.2mol/l over the last 3 months.
    Apart from the units (your meter also supplies its results in mol/l), this result has nothing to do with your instant readings on the day. They could be correct at the time.

    Most meters have a function to see the average of the readings over the last 7/14/30/60/90 days. The last 90 days is the one you should check.
    If that shows as 7.3ish then I'd suggest it is a pretty fair reflection.
    If it is significantly different, either, you are regularly missing something, or the meter is being a bit optimistic and you need to mentally add a couple of points to the answers.
     
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  13. neithskye

    neithskye Type 2 · Well-Known Member

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    Not sure. Here are the test results:

    Glucose Fasting HI 7.3 Reference: 3.6-6.0 Units: mmol

    Hemoglobin A1C/Total Hemoglobin HI 6.1 Reference: <6.0 Units: %
     
  14. neithskye

    neithskye Type 2 · Well-Known Member

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    I'm new to this and I don't think I'm explaining myself very well. I am not talking about my A1C. I am talking about the difference between the lab results for my blood glucose and my home meter results.

    Here are my lab results.

    Glucose Fasting HI 7.3 Reference: 3.6-6.0 Units: mmol

    Hemoglobin A1C/Total Hemoglobin HI 6.1 Reference: <6.0 Units: %

    For the past several weeks my home-tested BG has been in the 4-5 mmol range. On the day of the lab test:

    Home test, noon: 5.4 mmol
    Lab test, 1 pm: 7.3 mmol
    Home test, 2 pm: 4.8 mmol

    All I was wondering is how I got this 7.3 reading out of nowhere. I volunteered to see my doctor immediately when the office called so perhaps dashing around getting ready in a hurry raised my BG. I don’t know.
     
  15. HSSS

    HSSS Type 2 (in remission!) · Well-Known Member

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    Lol. So many numbers!

    Ok so your hba1c average of 6.1% corresponds pretty accurately with your on the spot blood glucose level the lab checked at 7.3mmol. Probably more of a coincidence than anything as you’ll have had plenty above and below that number to create an average.

    Yes stress can put numbers up so perhaps that was partly it. Also meters can be and are up to 15% inaccurate under lab conditions let alone real life. Although measuring instant here and now blood sugars the tests are not identical so maybe that explains a little too. It’s not perfect and it is frustrating.

    That all said as your hb1ac equates to an average of 7.2mmol and you’re only seeing 4’s and 5’s it’s either reading pretty low or you’re somehow missing the higher levels on your meter.
     
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  16. neithskye

    neithskye Type 2 · Well-Known Member

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    Yes, when I first started testing in July my results were in the 15-20 mmol range. Then 11-13 in late July. Then 9-10 in early August. And so forth. Now they're 4-5. Definitely improving!
     
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  17. HSSS

    HSSS Type 2 (in remission!) · Well-Known Member

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    Wow that’s a great improvement. Well done.
     
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