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Calibrating glucose meter

Galathea

Galathea

Member
Messages
20
Location
Weymouth
Type of diabetes
Prediabetes
Treatment type
Diet only
Hi all, I have been eating lw carb for the past three weeks, have lst almost a stone in weight and have just been tested for the doc by the hospital. I don't have all the results yet. ( I see the nurse on Monday). But it was a fasting test and immediately after giving blood, I tested with my own meter. I made my blood glucose. 7.5. But the hospital result is 6.3. (15 hour fast)

My meter is an accu-chek. Mobile. https://www.accu-chek.co.uk/gb/products/metersystems/mobile.html. And I have checked it with the testing solution they supply.

I see the nurse on Monday for a repeat test and I will check myself, using my meter at the same time. Do meter results vary wildly? Should I query the hospital result? Or should I query my own meter?

I am feeling much much better and I think I have pre diabetes.... despiite sometimes getting readings Iof 17 and 18 a few weeks ago..... They have come down to an average after meal reading of 8.5.

Anyone any ideas?

Thanks.
 
Hi, meter readings do vary, I can test on one hand & straight away on the other & have two different readings, say 6.2 & 5.4 , I can even use the same drop of blood and get 2 readings. Sometimes when people want a better idea they do a 3rd test and average it out x
 
Ah! . Are some machines known to be more reliable than others? If I get over the magic number 7 then the doc says there is a problem and I get free testing strips and if its under then I don't and I have to buy my own..

I shall continue on the low carb... Its making me feel so much better and my numbers are evening out a little.... At least the high spikes and the accompanying heart palipitations are gone......

Xx.
 
1)If you used a finger prick then you are actually using different blood. (venous v capilliary) There is a difference between glucose levels in these two 'types' of blood with venous blood having a lower concentration of glucose. The difference is not large at fasting but it is there . (There is a much larger difference after a meal)
2) All meters vary both in how consistent they are and how accurate they are. You get to know if a particular meter constantly throws up inconsistent readings (though I suspect that's not so easy to notice if you only test once a day) The legal requirements for meters actually allow for a very wide margin of error.http://www.diabetes.co.uk/blood-glucose-meters/blood-glucose-meter-accuracy.html, most of the well known makes actually do better than the legal requirements when tested
3) We are all human and the way we do the test can influence the results; so for example pressure (squeezing) can alter the blood sampled and therefore the result.
 
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I didnT know about the different measurements in veins and capillaries.... Wow! So the doctors tell us to test by finger prick but then they test by drawing blood through a vein..... Makes no sense at all. The guidelines give upper and lower limits for blood glucose but don't specify where it is to e drawn from.....

Is there anywhere I can read up about the difference? Do you know the names of any papers? Off to look at Dr Google!

Xx. G
 
That's why fingersticks aren't normally used for diagnosis.
Actually, as I T1,I've only ever had one lab fasting glucose test (that was at diagnosis but tbh at 22mmol/l, a finger stick would have given the same message since people without diabetes don't even reach double figures when fasting and only rarely after meals) The test most doctors use after someone is diagnosed is the HbA1c. If you are having regular lab tests for fasting glucose then they will show a trend. It's the same with your meter readings, they will vary from day to day but over time you can see if they are trending up or down .
two articles at different ends of the spectrum for detail.
http://www.diabetesofficevisit.com/2011/11/why-is-my-finger-stick-often-different.html
https://www.bestthinking.com/articl...e-between-arterial-capillary-and-venous-blood
.

edited (for clarity)
 
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phoenix said:
1)If you used a finger prick then you are actually using different blood. (venous v capilliary) There is a difference between glucose levels in these two 'types' of blood with venous blood having a lower concentration of glucose. The difference is not large at fasting but it is there . (There is a much larger difference after a meal)
2) All meters vary both in how consistent they are and how accurate they are. You get to know if a particular meter constantly throws up inconsistent readings (though I suspect that's not so easy to notice if you only test once a day) The legal requirements for meters actually allow for a very wide margin of error.http://www.diabetes.co.uk/blood-glucose-meters/blood-glucose-meter-accuracy.html, most of the well known makes actually do better than the legal requirements when tested
3) We are all human and the way we do the test can influence the results; so for example pressure (squeezing) can alter the blood sampled and therefore the result.
Click to expand...

I didn't know squeezing could influence the strip readings. Are they higher or lower? I almost always have to apply some pressure.
 
Squeezing local to the site introduces interstitial fluid into the blood on the strip test. This can be higher or lower than the blood level, depending on timing and the direction your glucose is moving.

Measuring glucose levels is not an exact science and although we like to think of it that way, we really shouldn't.
 
tim2000s said:
@phoenix, I was diagnosed of the urine strips . It was so high, they didn't need an hba1c...
Click to expand...
I went to this poor GP who I'm sure thought that I was totally crazy telling him I thought I had diabetes. I couldn't explain very well in French and I was 52 and (by then) very thin. He sent me away with a blood test form telling me to come back if the results were over 1.26g/l (ie 7mmol/l) . I don't think he expected to see me back. Within 2 hours of the test, the lab had faxed him , he called me in and sent me straight to hospital.
 
My father raised his concerns with the GP, who gave him the urine strips to check. I don't think they were quite expecting the result they got!
 
tim2000s said:
Squeezing local to the site introduces interstitial fluid into the blood on the strip test. This can be higher or lower than the blood level, depending on timing and the direction your glucose is moving.

Measuring glucose levels is not an exact science and although we like to think of it that way, we really shouldn't.
Click to expand...

Thanks for the explanation. I'm not taking my readings as 100% accurate but have used them since my diagnosis in January to watch my averages going down and to see what foods I needed to avoid (sadly includes porridge and home-made scotch broth with lots of barley). At least I'm hopeful that my next HbAic test will be a bit lower and the nurse will see that I've been making an effort. I'm also hoping I won't have to be put on medication (as she predicted).
 
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