Evaluating Analytical Performance of Biochemistry Tests Using Six Sigma Metrics in a Medical Laboratory

Introduction: Six sigma metrics is a quality tool used to evaluate the performance of a clinical laboratory.A six-sigma process is one in which 99.999666% of the products manufactured are statistically expected to be free of defects.It can be inferred that as the sigma score increases the consistency and steadiness of the test improve, thereby reducing the operating costs.This study was aimed at using sigma metrics to evaluate the analytical performance of our clinical laboratory by using internal quality control (IQC) as well as proficiency testing data of biochemistry tests.Materials and methods: Six-month data were retrospectively studied for 22 different biochemistry analytes.Percentage of coefficient of variation (% CV), percentage bias (% Bias) and total allowable error (TEa) were used to calculate the Six Sigma score.The Sigma score was calculated for both levels I and II of IQC.The average Sigma score was also calculated based on using the average of both level scores.Results: The study showed that out of 22 parameters, 13 tests had a Sigma score of greater than 6, while 9 had between 6 and 3.No test showed a Sigma score below 3. Conclusion: The study showed excellent analytical performance of all the tests on the current biochemistry testing instrument.Six Sigma metrics are a very good tool to monitor the analytical performance of an instrument.Total allowable error (TEa) is selected for monitoring.It also helps in redesigning the quality control strategy.