Nested control procedures for internal analytical quality control. Theoretical design and practical evaluation.

A quality control system has been developed and evaluated for three Greiner automatic analyzers. The control system was built in a hierarchical way with different statistical rules for different stages of the analytical process. Computer simulation techniques were found to be very helpful in grasping the quantitative aspects of various design features. In the practical evaluation of the control system the calculated rates of false rejections were of the same order as the theoretical value of 0.01 in most cases, and the estimated frequencies of analytical disturbances varied between 0 and 0.25.