How much of a difference can there be in a fasting report done by laboratory and an Accu-Chek home glucose meter?

In the United States, the monitors used to measure capillary whole blood glucose are programmed to give an equivalent level of serum glucose using a mathematical correction. However, there is a 20% error rate with these instruments. This was known at the time the Food and Drug Administration approved their sale in the U.S. The error is enough to help with management of diabetes, but it is not good enough to use as a methodological standard. Therefore, any time that measurements of blood sugar are made for the purpose of making the diagnosis of diabetes, a serum glucose needs to be run in a standardized clinical laboratory. When a patient uses the device for management, the precision is not as important as the trend in the follow-up values.

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