Proficiency evaluation of clinical chemistry laboratories.

The problem of proficiency evaluation of clinical chemistry laboratories is considered in terms of the accuracy, precision, and allowable limits of error of 10 common analytical procedures, and in terms of the proficiency of individual analysts and the occurrence of gross laboratory mistakes. The concept of the operational chart is developed, and its use is illustrated. Operational charts summarize basic quality-control information in a clear, concise, goal-oriented perspective which is useful for evaluating the performance of individual laboratories and for comparing groups of laboratories. The charts aid in identifying major problems relating to the reliability and clinical usefulness of laboratory results, and should facilitate managerial decision-making processes.