Sigma Metrics Assessment as Quality Improvement Methodology in a Clinical Chemistry Laboratory

Abstract

BackgroundThe concept of sigma metrics & lean six sigma is well known in the field of healthcare. However not many labs utilize the six sigma metrics for maintenance of high quality laboratory performance. A minimum value of 3 sigma is desired in any clinical laboratory & values of sigma[≥] 6 are regarded as gold standard for obtaining high quality lab reports. Aims &ObjectivesTo calculate bias, cv & sigma metrics from the IQC & EQC data in order to ascertain extent of quality management in our lab. Materials &MethodsAn extensive study of sample processing and quality practices was carried out in the Central Laboratory of Department of Biochemistry; PGIMER &Dr. RML Hospital, New Delhi; from Feb 2020 to July 2020. The IQC used(both level I & level II) were from Biorad Laboratories India (lyphochek assayed chemistry control) & the EQC used was from Randox Laboratories, UK. All the controls were run on Beckman Coulter clinical chemistry analyser AU 680. Total 14 clinical parameters were analysed & subsequently; Mean, S.D., CV, bias & sigma were calculated through their respective formulas. ResultsSigma level was more than 6 for both levels of IQC was observed for Amylase. It indicates world class performance. Total bilirubin, AST, Triglyceride & HDL depicted sigma values between 3.1 - 6 for both L1 & L2. Iron showed sigma value of 5.5 in L1 whereas it was 3.78 in L2. ConclusionSigma metrics in clinical laboratory is an essential technique to ascertain poor assay performance, along with assessment of the efficiency of existing laboratory process.