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4 different values taking 4 blood glucose readings in a row?

Y

Yogamommy5

Member
Messages
15
Type of diabetes
Type 2
Hi,

I was only diagnosed 2 months ago. I have an old meter from when I had pre-diabetes a year-and-a-half ago. The strips are 6 months out of date but I opened up a new package and tried to take a reading. I did eat something I probably shouldn't have which is fried plantains and I was expecting a spike as it has been about 90 minutes.

So I was only a little surprised to see a high reading of 9.9. After this I decided to test this meter by getting out my new meter (a different brand) and I got a reading of 10.7 my highest reading ever. The only time I got a 10.2 was after eating a full order of fries. So I took two more readings with my new meter on different fingers and they were 8.6 and 9.7. Is there something wrong with my meters? I know my reading should be high but why all this variation?

This morning I got an 8.4 and for the last three mornings I've been getting 8.4 to 8.8 and I've been surprised by that. I usually average around 7 in the morning before eating breakfast.
 
It's completely normal to get slightly different figures on two or more readings @Yogamommy5

The meters have a margin of error, and so your readings look fine. If you ever get a very surprising test result, then it's always worth washing your hands and retesting, but generally just accept that the figure you get wont be 100% accurate and will vary somewhat.
 
I believe that the accuracy of these meters is generally +/- 15%.
The average of your 4 readings is 9.7 and +15% of that is 11.2 and -15% is 8.3.
Your results are within expectations.
 
This is quite normal. All meters have to conform to the same ISO accuracy standards before they can be marketed, and basically this is they must be within 15% of the true value, either lower or higher 95% of the time. If your readings fall within this, they are fine.

http://www.diabetes.co.uk/blood-glucose-meters/blood-glucose-meter-accuracy.html

There are also other considerations. Human error and strip error. We all get the odd rogue strip from time to time. Human error is normally because we haven't washed, rinsed and dried our hands before each test.

To avoid confusion it is best to stick to one meter only. Put the other away to use in emergencies only. If your readings are within your normal standard, try to avoid re-testing, record the number and move on. If it is an unexpected reading, then yes, re-test.
 
What I don't understand about the accuracy....
If my meter with a given batch of test strips reads say 10% high compared with a laboratory instrument, then does it always read 10% high or with that same batch of test strips could it sometimes read up to 15% above the laboratory instrument and sometimes up to 15% below?
 

It can read anywhere within the 15% of the true, 95% of the time. The other 5% could read anything!
 
Bluetit1802 said:
It can read anywhere within the 15% of the true, 95% of the time. The other 5% could read anything!
Click to expand...
Consider this example.....
I measure my BG before dinner 5.8, I measure my BG 2 hours after dinner 7.7 = good only 1.9 mmol/L increase.
BUT my first reading was 15% high it was really 5.0 and my second reading was 15% low it was really 9.0 = bad it was a 4.0 mmol/L increase.
If this is the real accuracy then a lot of "eating to your meter" could be a waste of time.
 

I understand what you mean, but most readings are a lot nearer than the 15%. The 15% is the maximum allowed. All we are doing is looking for trends, and trends can't be found after a single reading. You need lots of readings, which is why I say it is all trial and error and it takes a long time. You also know approximately what your normal range is for any given time. So if you normally see 5 before a meal and you get 5.8, a re-test is appropriate.

It isn't worth haggling and stressing about. It would be wonderful if we had accurate meters, but we don't. We have what we have. (Be thankful it is now 15%. It used to be 20%. )
 
Most of the time it will probably be close enough. The real problem with eating to your meter is that you are only measuring blood glucose and not insulin levels. You can have acceptable blood glucose levels, but if you are pumping out excessive amounts of insulin to achieve that acceptable level, then that's not good. That's why I figure it's best to just keep my carb intake as low as possible, although I do experiment occasionally to see what carbs do to my blood glucose levels.
 
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