Accuracy

How close an experimental value is to the known value

Accuracy is defined in ICH Q2 Validation of Analytical Procedures as "the closeness of agreement between the value which is accepted either as a conventional true value or as an accepted reference value and the value measured" and "The closeness of test results obtained by that method to the true value" in USP <1225> Validation of Compendial Methods. This means a sample of a known concentration, or value, is tested on an analytical instrument. The result is then divided by that known concentration and multiplied by 100 to determine the recovery as a percentage. In analytical method validation it is required that triplicates of three different concentrations are tested to demonstrate that the method is accurate.