System and method for producing statistically valid assay means and ranges for quality control materials

A method of establishing a sampling plan for assigning an assay mean and range to a particular lot of a quality control material, the method comprising: setting an upper limit for the percentage of the assay range that is due to uncertainty in estimating the assay mean; accessing a database of historical test results obtained from tests performed on prior lots of the quality control material; computing at least in part from the historical test results a within instrument variability estimate that is an estimate of the variability of test results obtained using a single testing instrument on at least one prior lot of the quality control material; and computing at least in part from the historical test results a between-instrument variability estimate that is an estimate of the variability of test results obtained using different testing instruments on at least one prior lot of the quality control material; and establishing a sampling plan, based at least in part on the within- and between-instrument variability estimates, to achieve an assay range having a percentage of its width due to uncertainty in estimating the assay mean, the percentage being at or below the upper limit. LIMIT DATABASEOF AND RANGE HISTORICAL ASSIGNMENT RESULTS SYSTEM SAMPLING SAMPLE VARIABILITY PLAN PLANESTAB. ESTIMATION TESTSON MEAN RANGE TARGET NEW LOT DETER. ESTAB. PROB.