Sigma Metrics-Tool for Quality Assurance in Clinical Biochemistry Laboratory

Introduction: Sigma metrics is a quality management tool used for process improvement which usually comes into application when there is a measurable outcome in the process. It can play an important role in health care laboratory services as Quality Assurance (QA) of the same, is the need of the hour. Aim: To gauge the performance of a few biochemical parameters by calculating their sigma metrics on a sigma scale. Materials and Methods: This retrospective study was undertaken using Quality Control (QC) and External QA Scheme (EQAS) data for 17 biochemical parameters from Biochemistry section, diagnostic laboratory of an M.S. Ramaiah Medical College and Hospital, Bengaluru. Sigma values for these parameters were determined and sigma metrics was evaluated for duration of 13 months. Results: In level 1 coefficient of variation percentage (CV%), five parameters (ALP, calcium, magnesium, triglycerides and HDL-cholesterol) showed an ideal performance of ≥6 sigma level and in level 2 CV%, eight parameters (total bilirubin, urea, creatinine, albumin, AST, total cholesterol, total protein and phosphorus) showed a sigma of ≥6. Quality Goal Index (QGI) for 11 analytes in level 1 and seven analytes in level 2 was