OBJECTIVES:In clinical laboratories, sigma metric analysis is used to assess the performance of laboratory process system.The aim of this study was to evaluate the analytical process performances of the biochemistry tests in the Beckman Coulter-Olympus AU5800 by using the six-sigma methodology.MATERIALS and METHODS:The analytical performances of Beckman Coulter-Olympus AU5800 running 21 biochemical tests (Glucose, Urea, Creatinine, Total Bilirubin, D. Bilirubin, Total Protein, Albumin, Uric acid, SGOT, SGPT, LDH, GGT, T.Cholesterol, HDL, CK, Na, K, Cl, Ca, P and Mg ) were evaluated.The six month internal(level1-2) and external quality control programs were extracted for these parameters.CV% was obtained from internal quality control programs.Percentage bias for these parameters was calculated from external quality control programs.Total allowable errors were followed as per CLIA guidelines.Sigma metrics were calculated from CV%, percentage bias and total allowable error for the above mentioned parameters.RESULTS:For parameters T.bilirubin, D.bilirubin, uric acid, SGOT, SGPT, ALP(level 2), CK, Mg, HDL and LDH, the sigma values were found to be more than 6.For parameters glucose, albumin(level2), ALP(level 1), Cl, T.Cholesterol, P, Na(level2) the sigma values were found to be between 3 to 6.The sigma values were found to be less than 3 for parameters total protein, albumin(level1), Na(level1) K, creatinine and urea.CONCLUSIONS:To improvement and monitoring of the analytical process performance clinical laboratory to provide continuous improving, sigma levels can be used.Analytes with the sigma value < 3 are required strict monitoring and modification in quality control procedure.