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Normal blood tests?

Discussion in 'Prediabetes' started by Glink, Sep 8, 2017.

  1. Glink

    Glink Prediabetes · Well-Known Member

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    I just got my quarterly lab report, and my FBG was 5.5, HbA1C 5.3. I am really surprised, because I've been feeling lousy lately and noticing highs postprandially as well as in the mornings, and I haven't been as careful with carbs this month on holidays as usual, so I was braced for bad news.

    It sounds great, but I'm not sure it adds up:

    This morning I tested at 7am at home: 6.7. My blood draw wasn't for another hour and a half, at 8:30. I brought my test kit and did it right after, which I usually do to check that my metre is accurate. My metre said 6.3.

    So, metre must be off, right? But, tonight I checked it against my spare metre at home and they are calibrated together. Both gone off the same amount at the same time? Seems odd.

    Any thoughts? Worry less about the carbs? Just wait until my next round of tests to see what they say? I've been warned that I'm probably pre-LADA so I'm always waiting for the other shoe to drop, and was really not expecting to see my first normal text in 2-3 years.
     
  2. pavlosn

    pavlosn Type 2 · Well-Known Member

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    Monitors for self testing work on capillary blood while your lab test is on blood drawn from a vein. This may account for the difference.

    Hba1c is a different fruit altogether as it is a three monthly average and so has nothing to do with what your monitor is showing on the day of the test.

    Sent from my SM-G935F using Diabetes.co.uk Forum mobile app
     
    • Agree Agree x 2
  3. pleinster

    pleinster Type 2 · Well-Known Member

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    Good advice from @pavlosn - a meter test is only giving you an indication of your blood sugar at a given moment (and meters have a margin of error to bear in mind) and the HbA1c gives the average pretty accurately over a three month period. Add to this the fact that morning is not the best time to test due to the fact that the liver can and often does dump glucose into the system to prepare your body for the day ahead; the morning level is not always the lowest of the day. My advice would be don't ease up too much on the low carb approach (if that's what you mean by worrying less about carbs but do worry less and don't be too hard on yourself if you "slip up") but be happy your levels are reasonable. And be delighted with the HbA1c of 5.3.
     
  4. Bluetit1802

    Bluetit1802 Type 2 (in remission!) · Guru

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    I would trust the Fasting BG test done at the surgery as it was (presumably) taken from your arm and analysed at the lab. Your finger pricking meter is only a snap shot and not as reliable as one tested at the lab.

    Just as an aside to what @pavlosn was saying about capillary blood and venous blood, this doesn't apply any more. Meters these days (sometimes strips) are calibrated to convert the capillary whole blood level to a plasma venous blood level.

    I think you are saying your lab results are lower than you were expecting? The HbA1c doesn't work well for everyone. If you have any sort of red blood cell "abnormalities" this can sway the result. You can check your full blood count markers on a print out if you have one and check for yourself how normal they are, or otherwise.
     
    • Informative Informative x 1
  5. Resurgam

    Resurgam Type 2 (in remission!) · Expert

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    Perhaps previous good behaviour has helped - maybe the hot weather, more exercise, or simply the passage of time has had an effect.
    Personally I know that I can eat more carbs these days without raising my BG, but I still remain fairly low carb as I know that higher carb foods will mean weight gain - having thrown out my larger sized clothing I would be in something of a quandary if I began to increase in size at the rate I know is possible. An extended period of high carb eating would no doubt push up all my diabetes symptoms and blood test results, so I just keep on with the way of eating - it makes sense.
     
    • Agree Agree x 1
  6. Glink

    Glink Prediabetes · Well-Known Member

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    I understand the hba1c being different from a given blood glucose test (and yes 5.3 is fantastic and I don't want to look that gift horse too far in the mouth!*), but I'm wondering more about my metres reading so far off of the FBG from the lab, which has never happened before. At home my FBG readings have been hovering around 7 at 7am lately, but 5.5 (albeit at 8:40am) is downright normal! I don't really know how to interpret that unless I just chuck my home metres all together. Maybe I'll take a vacation from testing for the next 3 months (without radical diet changes, but trying not to fret too much) and see how that goes. If the margin of error on my metre is that large that it spans the range from normal all the way through prediabetes into diabetic #s (e.g., FBG of 5.5 to 7) then testing seems of little use anyway.

    *Someday when the Libre is available here in Canada I may invest in that to see a couple weeks' round-the-clock readings to better understand what wonky thing I've got going on, but for now I'll just take the surprisingly good HbA1c--I've always read lower on that test than would be expected by my other metrics.
     
    #6 Glink, Sep 8, 2017 at 9:48 PM
    Last edited: Sep 13, 2017
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