A quality control simulator for design and evaluation of internal quality control procedures.

A computer simulation program has been developed to aid clinical chemists in the design and theoretical evaluation of statistical control procedures. This "QC simulator" permits the user to study the effects of different parameters characterizing the measurement procedure (method standard deviation, components of variation, rounding of results) and parameters of the control procedure (decision criteria, control limits, number of observations). The performance of control procedures is characterized by the probability for rejection, estimated at several different levels of random and systematic error. Predictive values for reject and accept signals are also calculated at different error incident rates, given a specified error model. The relative performance of different control procedures can be compared based on these performance characteristics. Another important application of the program is the design of control procedures to assure that a specified level of analytical quality is achieved in routine analyses. Various optimization criteria may be applied, e.g., in terms of test yield and cost.