different bg reading - DAFNE Online

January 29, 2014 16:50

john m DAFNE Graduate
Northern Care Alliance NHS Foundation Trust – North East Sector Hospitals 15 posts

i tested my bg 3 times yesterday and got 3 different readings at 15 29 it was 17.3 at 15 35 it was 13.6 at 15 36 it was 15.5 why and what is the rite one Sad

January 30, 2014 12:27

novorapidboi26 DAFNE Graduate
NHS Lanarkshire 1,819 posts

I would probably chose the one in the middle........

Did you wash your hands before the test.....

Its normal for there to been a mmol or two difference between test/fingers...

Why did you test 3 times in such a short period..?

January 30, 2014 16:39

john m DAFNE Graduate
Northern Care Alliance NHS Foundation Trust – North East Sector Hospitals 15 posts

i always wash my hands never have a reading as high as 17 tested for ketones which was low so i checked a 2nd time which gave me a reading of 13 3rd time was just curious

January 31, 2014 13:14

novorapidboi26 DAFNE Graduate
NHS Lanarkshire 1,819 posts

just one of these things maybe.....

February 03, 2014 01:04

Warwick DAFNE Graduate
Diabetes Australia-Vic, Melbourne, Victoria 423 posts

BG meters have to be accurate to within 20% of the true range which is a really high range of error. Even if you use control solution, there will be variance between two consecutive readings.

Given that it isn't that long ago that urine testing was the norm, hopefully it won't be long until there is a new generation of blood testing meters that are accurate to within 5% or lower.

February 03, 2014 11:26

Garry DAFNE Graduate
North Lincolnshire and Goole NHS Foundation Trust 328 posts

Most manufacturer control solutions have a huge range of acceptable results from the meter..."only send us the meter back if outside the range 13.8 to 21.2." What!! I thought at the time, what kind of an acceptable test range is that supposed to be?
Repeat tests using the test solution however, gave me a set of results that did not vary by more than 1 mmol. Meter manufacturers talk about 'precision' and they mean statistical precision...or repeatability.
We always think of accuracy and I have to admit that the language that manufacturers use is deliberate to obfuscate and baffle us into thinking that their meter is the best thing since sliced bread...It ainâ€™t. All they mean is that their meter can potentially give us the wrong answer....repeatedly.
Regards
Garry

February 08, 2014 15:39

Peter DUAG Committee Member
University College London Hospitals (UCLH) 109 posts

The other factor which may have an impact is whether you squeeze the finger to promote faster/sufficient blood flow. The meter manufacturers advise against doing this but, in my case, without doing so I'd have insufficient blood to perform a test much of the time and so I ignore that advice. However, I guess, that if you were inconsistent in how you obtained the sample then that could have played a part in the range of figures. The biggest reason, as others have said, is likely to be the unreliability of the meters.

January 29, 2014 16:50 john m DAFNE Graduate Northern Care Alliance NHS Foundation Trust – North East Sector Hospitals 15 posts	i tested my bg 3 times yesterday and got 3 different readings at 15 29 it was 17.3 at 15 35 it was 13.6 at 15 36 it was 15.5 why and what is the rite one
January 30, 2014 12:27 novorapidboi26 DAFNE Graduate NHS Lanarkshire 1,819 posts	I would probably chose the one in the middle........ Did you wash your hands before the test..... Its normal for there to been a mmol or two difference between test/fingers... Why did you test 3 times in such a short period..?
January 30, 2014 16:39 john m DAFNE Graduate Northern Care Alliance NHS Foundation Trust – North East Sector Hospitals 15 posts	i always wash my hands never have a reading as high as 17 tested for ketones which was low so i checked a 2nd time which gave me a reading of 13 3rd time was just curious
January 31, 2014 13:14 novorapidboi26 DAFNE Graduate NHS Lanarkshire 1,819 posts	just one of these things maybe.....
February 03, 2014 01:04 Warwick DAFNE Graduate Diabetes Australia-Vic, Melbourne, Victoria 423 posts	BG meters have to be accurate to within 20% of the true range which is a really high range of error. Even if you use control solution, there will be variance between two consecutive readings. Given that it isn't that long ago that urine testing was the norm, hopefully it won't be long until there is a new generation of blood testing meters that are accurate to within 5% or lower.
February 03, 2014 11:26 Garry DAFNE Graduate North Lincolnshire and Goole NHS Foundation Trust 328 posts	Most manufacturer control solutions have a huge range of acceptable results from the meter..."only send us the meter back if outside the range 13.8 to 21.2." What!! I thought at the time, what kind of an acceptable test range is that supposed to be? Repeat tests using the test solution however, gave me a set of results that did not vary by more than 1 mmol. Meter manufacturers talk about 'precision' and they mean statistical precision...or repeatability. We always think of accuracy and I have to admit that the language that manufacturers use is deliberate to obfuscate and baffle us into thinking that their meter is the best thing since sliced bread...It ainâ€™t. All they mean is that their meter can potentially give us the wrong answer....repeatedly. Regards Garry
February 08, 2014 15:39 Peter DUAG Committee Member University College London Hospitals (UCLH) 109 posts	The other factor which may have an impact is whether you squeeze the finger to promote faster/sufficient blood flow. The meter manufacturers advise against doing this but, in my case, without doing so I'd have insufficient blood to perform a test much of the time and so I ignore that advice. However, I guess, that if you were inconsistent in how you obtained the sample then that could have played a part in the range of figures. The biggest reason, as others have said, is likely to be the unreliability of the meters.