Hi everyone,
Weird question, but have you ever done 2 BGL readings right after each other, but on different hands? I just did (and yes, I washed my hands first), and got a reading of 175 on my left hand, and 153 on my right. And my CGM said 191.
Help?!
Hi Pixie. Sigh. The only thing that multiple testing will do is drive you crazy and waste test strips. What I would do, is take your 2 meters to the lab whenever you go. Do this a few times. Then you will know which bg meter (cgms have more variables - so just check the machines) is more consistent and accurate. When I had my cgm many years ago, I knew that my own meter read between 4 - 6% higher than the lab. My cgm was off my meter by 40% consistently so I ended up getting rid of it. You need to have something known, to compare the various readings of the cgm to and know how often those readings are that close.
Thanks Cora!
I'll have to remember that. I've only had the cgm for 5 days, so I'm still trying to get used to it and get the nuances of calibration down. I'm using more as a guide than anything else at the moment.
I just hadn't run into the ridiculously different readings before. Same meter, just different hands! So weird!
Repeatability is one way of evaluating BG meters. You could have used the same blood drop and possibly gotten the same different results. Very frustrating. I currently use Freestyle and find that my two tests are usually pretty close. Verio IQ and Lifescan Ping meter had much more variation.
I think it will never be an exact science since BG level change not only with physical activity, but with body activity itself. It could be one number in one part of the body and a different number in the other part, changing with the blood flow. Once, I checked BG from 3 fingers on one hand within 1-2 minutes. The readings were 10 points different from each other and none of them were the same.
I remember Consumer Reports, in their health edition, gave ratings on glucose monitor's accuracy.
I'm T2, but this is common for us, too. As Cora said, the inconsistencies can make you crazy. And I, too, check my meter against lab results whenever I can. So I know that my meter can read up to 15 points lower than a lab test. So I factor that in. This is exactly why we all "agitate" for better meters whenever we can......Blessings....
Yes, Dmitri. I am T2, but I want to know these things, too. So, for instance, I tested every few seconds over the course of a hot flash once, using the same finger for consistency: My number rose by 18 points and then slowly over 10 minutes dropped back to it's exact starting place---used up my strip allotment very fast, but as a "woman of a certain age," it was a very important series of #s for me.....Blessings
Pssst... you broke the "code". Guess what the venous blood draw would give you re: a reading
Meter Accuracy?
I have sometimes done 2 readings on the same blood drop (Dexcom requires 2 calibrations when you start a new sensor and on a couple of occasions I have measured the same fingerstick twice). Sometimes the two readings have differed by >10%.
I use an Abbott Freestyle Lite meter, which came out near the top of a recent published analysis of meter accuracy, and meets the latest European standards, so this demonstrates the limit of the technology.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3570840/pdf/dst-06-1060.pdf
CGM readings are even less accurate.
Joel
The new meters are not very accurate and measuring BG in a small blood drop
= trouble. The blood drop consist of liquid and solid compounds, the strip
pulls the sample using surface tension and the result is based on a sample
containing about 40% hemocreat...changes in surface tension effect the sample
and drawing a second sample from the same drop is even worse because the strip
does not draw in liquid and solids in equal proportions, so the second test will
be diffrent. Some meters make adjustments for hemocreat concentration and some do
not.
I use the Bayer meters because they correct for lower hemocreat (red blood cells), my
RBC is low so if I use a One-touch meter it will give me a 50 point higher reading
because it does not compensate for my low hemocreat level. I used One-touch meters
for many years with great success but after my transplant my CBC's have not been
normal and was forced to find a meter that would give me correct readings, if I dose
using a One-touch meter my BG is constantly low.........YMMV