I have two different brands of glucometers. Both QC correctly according to manufacturer's instructions — one even has a control solution. Results vary by 30 to 40 with these machines. Which one would be most accurate?
All blood glucose meters are allowed by industry standards to be 15% to 20 % off. In other words, any time you are checking with a meter the reading can be off by that amount. People think there is one blood gluocse number, but in reality, meters just give us an estimate of what the actual blood glucose is -- so for this reason, it’s not that helpful to compare one meter to another. When using the same meter, you can compare one reading to the next, and when doing this, we would not expect the number to vary more than 20 %. If you find your readings are varying by more than this, you may want to get a new meter. Blood glucose meters are required by the Food and Drug Administration (FDA) to meet certain minimum accuracy standards in order to be approved and sold, so in general, all meters are equally accurate. If you are getting a lot of variation in the numbers, make sure you are getting enough blood onto the strip, as an inadequate sample can give you a falsely low reading. Also, make sure you are washing your hands with soap and water before you check because food residue on the hands can give you a falsely high reading.