In the clinical laboratory, the coefficient of variation is used for two main purposes:

• to aid in the selection of a new method for routine use
• to monitor the inherent variability (precision) of a method already in routine use

Selection of a new method for routine use requires comparative precision data. If the two methods being compared have different means and/or units, calculation of their CV's provides the comparison. (However, if two methods have the same units, and measure the same quantity, but have different means, this could be a sign that one of the instruments is miscalibrated.)