Six Sigma metrics as an indicator for Randox International Quality Assessment Scheme in clinical biochemistry laboratory: A pilot study with thyroid function test in a tertiary care hospital

Context: Six Sigma methodology represents an evolution in quality assessment and management that has been implemented widely in industry and health sector since the mid-1980s. It consists of five steps: define, measure, analyze, improve, and control (DMAIC). Randox International Quality Assessment Scheme (RIQAS) program Target Score (TS) is a performance indicator, and Sigma metrics is considered as a gold standard for overall performance. Aim: The aim of this study is to present the TS and Sigma metrics observed in clinical chemistry laboratory in SSK Hospital associated with Lady Hardinge Medical College to evaluate the analytical performance of T3, T4, and thyroid-stimulating hormone (TSH) parameters. The study period is from June to August 2022. Materials and Methods: The Sigma metrics for the various analytes was calculated by the following equation: Σ = TEa − bias/CV (TEa—total allowable error, CV—coefficient of variation). Acceptable performance criteria: standard deviation index (SDI) <2; TS >50; the closer a value is to 120, the better the performance, <40 is unacceptable; and %deviation should be less than the defined acceptable limits which is unique to each analyte, the closer the value is to zero, the better is the performance. Results: Our RIQAS results lie in acceptable range except for T3 in the month of August in which TS was unacceptable. Our laboratory Sigma metrics were below three sigmas. The findings of our exercise emphasize the need for a detailed evaluation, and we promote the use of Sigma metrics in quality assurance in the best interest of the patient. Conclusion: Quality check strategies were applied according to the TS and sigma values.