A-195 The Application of Six Sigma Metrics to Assess Quality Control of Syphilis Tests in a Clinical Laboratory

Abstract

Abstract Background Clinical laboratories use quality control processes to monitor and evaluate analytical performance in terms of precision and bias. The periodic measurement of those parameters plays an important role in patient safety and it is a requirement in most accreditation organizations. In recent years, Six Sigma metrics has become one of the most efficient tools to monitor the analytical performance of clinical laboratory systems, since it unifies Total Allowable Error (TEa), random and systematic errors in a single index. However, for many analytes, TEa is not available in the literature based on effect of analytic performance on clinical outcomes or in biological variation. In this case, the TEa must be derived from the “state of art”. In this work, it will be described how Six Sigma was established in our laboratory for Syphilis, with TEa derived from external quality assessment program. Methods A year worth of data was gathered from internal quality control and external quality assessment evaluation to assess the imprecision (in terms of coefficient of variation—CV%) and bias for Syphilis tests processes in four modules of Alinity I (Abbott). Data was split into two groups: “Non-reactive” and “Reactive”. TEa was calculated from the external quality assessment for both groups, based on the median CV% of the peer group evaluated in the last 2 years. Six Sigma metrics were calculated from TEa, CV% and bias for each equipment, using the formula Sigma = (TEa-bias)/CV%. Results TEa for “Non-Reactive” and “Reactive” levels were estimated at 44,25% and 17,7%, respectively. Six Sigma values calculated for “non-Reactive” level were between 4,6 to 5,38 in every equipment. For “Reactive” level, calculated Six Sigma ranged from 4,24 to 5,82. All values found were classified as Good and Excellent according to the Normalized method decision chart. Conclusion Six Sigma is a powerful tool to monitor the analytical performance of the exam. For Syphilis, it is important to monitor “Non-Reactive” and “Reactive” levels separately for a better control over the analytical system. Abbott’s Syphilis test has also a satisfying performance in our laboratory. Also, estimating the TEa from external quality assessment programs is a good alternative for analytes with no quality specifications available in the literature.