Accuracy, as stated above, is an evaluation of the device to measure it up to existing standards. Precision evaluates the device against itself. Accuracy comes into play with the initial acceptance of the device. In order to accept the device, it should be confirmed that it complies with existing standards. The accuracy of the device qualifies how it performs in comparison to existing values.
Precision is the next step before completely accepting the device, as it must be confirmed to be consistent with itself. With precision, the FDA will evaluate if the device is properly functioning not just the first or third or last time it is tested but every time. The values attained must continue to hit the standard achieved with accuracy. For a medical device to be officially accepted, it must hit both accuracy and precision.