Proposals and current practices in quality control.

The current status of quality control in clinical laboratories is discussed, and selected new techniques for quality control and presented from the literature of the last six years. The concept of quality control is broadened beyond the running of control materials for validation of test runs. Methods for recognition, identification, and reduction of both process error are presented. Examples are presented of improvements utilizing graphic techniques, manipulation of control and check sample sera, statistical techniques for interpretation of trends, quality control action rules for the detection of out-of-control situations and method evaluation.