Blood Gluclose Mis-Readings

Hi everyone,

I'm just having one of those regular diabetic days which we all tend to have with our special condition. When I woke up this morning I was feeling kind of good, had a nice meal the night before, administered what I felt and calculated to be the correct dosage from my NovaoRapid FlexPen and went happily to sleep.

Upon checking my readings the next morning, my Optium Xceed meter told me that I was 18.7mmol/L and to check for Ketones. As you do, I immediately started to feel worse then I did a few minutes ago. I headed to my dresser to fix myself a dose of NovaRapid to counter this terrible reading but half way there I deceided, wait a minute, I don't feel bad so why not re-check my reading as I sometimes do when I'm low, partly because when I'm low I can't believe my readings to be 1.7mmol/L.

So in goes a fresh strip with fingers wiped down just in case and a new blood prick. New reading....9.1mmol/L. That is half of what the original reading was, so without fail I tested again 30 seconds later with the same bloody finger.... 7.1mmol/L. Not surprising to some maybe but to me it has made me wonder. .....What if our readings are wrong most of the time? This worries me most because the majority of my efforts are based on what I read from this monitor.

Do we put so much trust into a device that may be deceiving us through it technical faults?

Any thoughts, stories or advice on a meter that you find more precise, please add to the post.

All the best,


As a fundamental principle of metrology… it’s not a question of “is the reading wrong?” but “how much is it wrong by?”. This isn’t accounting, where your bank balance might be known to be exactly $1234.56, and if there is only $1234.55 then somebody was cooking the books.

Google for “Clarke Error Grid” or go to The Wikipedia Page for the Clarke Error Grid to see how blood glucose meter accuracy is thought of.