Now, don't you think this is silly - of course, everyone wants a test result to be accurate. The problem is that no test is perfectly accurate all the time. Consequently,most laboratories will retest any results that look suspicious when compared to other test results from the same patient. This may take a little longer but it is well worth the added time. If accuracy is hitting the bulls-eye, then precision is how often you can repeat the throw.
Most tests have a small variation of precision.
This variability is insignificant to the physician. Typically, precision is determined by testing one sample multiple times and then calculating the range of variation. This range is sometimes called the range of reproducibility and is used to separate clinically significant versus insignificant changes. The perfect test looks at one compound only. But perfect tests seldom happen.