Laboratory quality control: use of Shewhart charts and ANOVA

For years industry has used the Shewhart charting system for determining precision and accuracy of industrial products. This method has been adapted to the clinical laboratory, in this project setting, and coupled with analysis of variance (ANOVA). The yield is an in-house quality control (QC) system that graphically shows ongoing precision and accuracy, gives limits of control based on the capabilities of procedures used in three of St. Luke's laboratories, shows within-day and between-day variation, and can be used for evaluation of new methods. The system not only points out problem areas, but enables inexperienced personnel to see when problems exist.