Differing BG Readings - Different Meters <>5.0mmol

[Rol]

I'm a bit concerned at the differing readings I have been getting from my BG Meters and wondered if others have found the same.

I'm not sure whether I can name the devices but the one I have been using for a couple of years has always given me what I thought were sound readings. And when I have ever tested twice they would be either the same or point something different, giving me a sense of accuracy.

But my diabetes clinic has given me a different brand, this has given me readings at least 5.0mmol higher than my old meter. And then when testing again dropped by 3.0mmol. On looking back in my diary this meter was one I had had before and it was exactly the same. This reminded me why I had gone back to my old meter in the past.

I got a new version of my old brand of meter and both the old meter and the newer version had near same figure on a test. With the same sample of blood I did a test on all three meters, and again the one given to me from my diabetic clinic was a great deal higher than my original and newer version of the original meter. We are talking again around a good 5.0mmol difference.

As I am not currently at a well controlled level and the figures are in the range of 10 and 16mmol or 21mmol if you believe the clinic given meter, should this amount of difference happen? If I happened to be below 4mmol, would the clinic given meter still be 5mmol higher? I find this rather concerning.

 

[Bruce Stephens]

As I am not currently at a well controlled level and the figures are in the range of 10 and 16mmol or 21mmol if you believe the clinic given meter, should this amount of difference happen?

That's the problem. If and when you're more in the normal range, you should expect meters to give more similar (and useful) readings. When a meter says 16 or something I wouldn't read too much into the specific value: read it more as "too high". The meters and test strips are designed to be most accurate in the normal range and they're worse outside it.

 

[Leadinglights]

I'm a bit concerned at the differing readings I have been getting from my BG Meters and wondered if others have found the same.

I'm not sure whether I can name the devices but the one I have been using for a couple of years has always given me what I thought were sound readings. And when I have ever tested twice they would be either the same or point something different, giving me a sense of accuracy.

But my diabetes clinic has given me a different brand, this has given me readings at least 5.0mmol higher than my old meter. And then when testing again dropped by 3.0mmol. On looking back in my diary this meter was one I had had before and it was exactly the same. This reminded me why I had gone back to my old meter in the past.

I got a new version of my old brand of meter and both the old meter and the newer version had near same figure on a test. With the same sample of blood I did a test on all three meters, and again the one given to me from my diabetic clinic was a great deal higher than my original and newer version of the original meter. We are talking again around a good 5.0mmol difference.

As I am not currently at a well controlled level and the figures are in the range of 10 and 16mmol or 21mmol if you believe the clinic given meter, should this amount of difference happen? If I happened to be below 4mmol, would the clinic given meter still be 5mmol higher? I find this rather concerning.

With levels so high then try to focus on getting your diet and medication sorted out rather than worrying too much on the readings different monitors are giving you. Looking for trends rather than individual readings and stick with just one monitor. Check things like is the battery OK, are your test strips in date and making sure you have washed your hands before pricking your finger.
For some monitors you can buy control solution to check if they are within the permitted accuracy.
But the higher your readings the greater will be the range that is permitted i.e. +/- a particular value.
I believe the Sinocare is a monitor which people have had problems with.
GlucoNavii, TEE2 and Contour Blue are monitors which people have found pretty reliable.

You can see the variations you might expect in the table in this thread.

Post in thread 'Same food, same time of day, different post- glucose levels, WTF!'

Apr 1, 2025

@TMR254 - What you eat might be a big one, but there are lots of other things going on that affect your blood glucose at any time. Added to that is the error associated with the meter reading and the message is, don't try and be too cute in trying to work out what the numbers mean.

The meter is an amazing piece of kit and I think it wonderful that it can give a reading anywhere near your blood glucose. But....

My thought for anybody trying to interpret meter readings is first round the reading to the nearest whole number and then begin to think that something is worth thinking...

• Docb

• 

 

[harbottle]

The error margin is a percentage of the 'lab' reading, therefore the higher the reading, the higher the margin of error is allowed. So it's possible different devices can show a deviation of that much - it depends on the quality of the electronics, the quality of the strips, the enzyme used, the algorithm in the device, etc.

Some are more accurate that others as well. (And as has already been stated, they are designed to be more accurate at normal levels - < 5.6 the deviations from the lab result is .8, not a percentage.)

 

[helli]

This is the table the shows the "accepted" variation in BG while still conforming with the standard.
Note: if your BG is at the top end, the difference between two confirming meters can be more than 5mmol/l

 

[Rol]

This is the table the shows the "accepted" variation in BG while still conforming with the standard.
Note: if your BG is at the top end, the difference between two confirming meters can be more than 5mmol/l

View attachment 34933

Thank you so much, this makes a lot of sense.

 

[louisew]

This is the table the shows the "accepted" variation in BG while still conforming with the standard.
Note: if your BG is at the top end, the difference between two confirming meters can be more than 5mmol/l

View attachment 34933

Blimey, I have tight control so my blood sugar is usually between 4.5 and 6. But my libre almost always reads it exactly 1 mmol lower than a finger prick so according to this it’s pretty inaccurate. I’m usually happy with readings in the 4s but finger prick under that figure. Obviously I finger prick before driving. My shuggah app often shows a high percentage of readings as low when actually I’m nearly always 100% in range.