Quality indicators and specifications for key analytical-extranalytical processes in the clinical laboratory. Five years' experience using the Six Sigma concept.

Background: The results of 5 years of experience (2004-2008) with process-based quality management using quality indicators for key laboratory processes (analytic and extra-analytic) in a group of clinical laboratories affiliated with the Catalan Health Institute are presented. Our purpose was to analyze the evolution of the indicators, identify processes that require corrective measures, and obtain specifications that are more robust than the preliminary ones proposed in a previous study by the same group.

Methods: The yearly average was recorded for each indicator in each laboratory, the yearly interlaboratory median was calculated, and the changes occurring were studied to determine their continuity in the 5-year period.