Evaluation of Quality Performance of Hematology Laboratory Testing by Using Sigma Metrics
Keywords:
Quality control, Sigma metrics, HematologyAbstract
Analytical performance of clinical laboratory analyzers should be routinely assessed to ensure the validity and quality of laboratory results. The aim of this study was to assess the analytical performance of the Mindray BC6200 automatic hematology analyzer in the Hospital for Tropical Diseases by using sigma metrics. The sigma metrics of hematology parameters were calculated from internal quality control (IQC) results and external quality assurance scheme (EQAS) data retrospectively from January to December 2023. The precision and accuracy of white blood cell count (WBC), red blood cell count (RBC), hemoglobin (Hb), hematocrit (Hct), and platelet count (PLT) were aligned within the acceptable limits. The average sigma metrics achieved for the selected parameters, WBC, RBC, Hb, Hct, and PLT, were 6.5, 7.8, 6.7, 5.4, and 7.9, respectively. These results indicated the laboratory achievement at excellent to world-class performance. This performance achievement enabled the laboratory quality control practice to be simpler and to operate with lower budgets. Application of Westgard multirules for high error detection with low false rejection rates was recommended. This study revealed that using sigma metrics as a tool for assessment of analytical performance in a clinical hematology laboratory could enable laboratories to plan continuous quality improvement and to reduce replications and budgets of the IQC process.
References
International Organization for Standardization. ISO 15189 – Medical Laboratories: Requirements for Quality and Competence. 4th ed. Geneva: ISO; 2022.
Westgard JO, Groth T, Aronsson T, Falk H, de Verdier CH. Performance characteristics of rules for internal quality control: probabilities for false rejection and error detection. Clin Chem 1977; 23: 1857-67.
Charuruks N, Wanachiwanawin D. Quality control analysis in clinical laboratory: from theory to practice. Bangkok: Ruenkaew Printing; 2005. (in Thai)
Westgard Rules and Multirule Quality Control. [Internet]. [cited 2024 Apr 07]. Available from: https://www.westgard.com/westgard-rules.html
Westgard JO. Six Sigma Quality Design and Control. Desirable precision and requisite QC for laboratory measurement processes. Madison, WI: Westgard QC Inc.; 2001.
Park SH. Six Sigma for Quality and Productivity Promotion. Tokyo: Asian Productivity Organization; 2003.
Khaongamdechawat S, Siriprukpong P. Efficiency of the QC procedure using OPSpec Chart and Sigma Metric QC planning tool. J Med Tech Assoc Thailand 2013; 41: 4548-63. (in Thai)
Sirithansakul T. Assessment of hematology and clinical chemistry laboratory performance by six sigma metric; Department of Medical Technology, Trang Hospital. J Med Tech Assoc Thailand 2019; 46: 6349-74. (in Thai)
Satsuk C, Treebuphachatsakul W, Kongros K, Chuaychoo P, Tabklai U, Apiratmateekul N. Performance evaluations and costs for internal quality control of the hematology laboratories in regional hospitals by using sigma metrics. J Med Tech Assoc Thailand 2022; 50: 8316-56. (in Thai)
Daly S, Graham PA, Freeman KP. Quality control validation for a veterinary laboratory network of six Sysmex XT-2000iV hematology analyzers. Vet Clin Pathol 2022; 51: 565-76. doi:10.1111/vcp.13163.
Berta D, Melku M, Adane T, et al. Analytical performance evaluation of hematology analyzers using Sigma metrics. PREPRINT (Version 1) at Research Square [Internet]. 2023 June 25. Available from: https://doi.org/10.21203/rs.3.rs-3067038/v1
Ozdemir S, Ucar F. Determination of Sigma metric based on various TEa sources for CBC parameters: the need for Sigma metrics harmonization. J Lab Med 2022; 46: 133-41. doi:10.1515/labmed-2021-0116.
Westgard JO, Carey RN, Wold S. Criteria for judging precision and accuracy in method development and evaluation. Clin Chem 1974; 20: 825-33.
Westgard JO. Calibration verification criteria for acceptable performance. [Internet]. [cited 2024 Jul 08]. Available from: https://westgard.com/lessons/basic-method-validation/733-cal-verification-criteria.html
Westgard JO. Basic method validation. Basic validation of qualitative tests. [Internet]. [cited 2024 Jul 08]. Available from: https://westgard.com/lessons/basic-method-validation/753-validating-qualitative-tests.html
CLIA Proposed Acceptance Limits for Proficiency Testing. Westgard. [Internet]. [cited 2024 Sep 07]. Available from: https://www.westgard.com/2024-clia-requirements.htm
Westgard JO. Consolidated Comparison of Hematology and Coagulation Performance Specifications. [Internet]. [cited 2024 Jul 08]. Available from: https://westgard.com/clia-a-quality/quality-requirements/802-hematology-goals.html
Kalra J, Kopargaonkar A. Quality improvement in clinical laboratories: a Six Sigma concept. Pathol Lab Med Int 2016; 1: 11-20.
Westgard JO, Westgard SA. Basic Quality Management Systems. Chapter 12. Designing SQC procedures. Madison, WI: Westgard QC, Inc; 2014.
Goel S, Nisal AR, Raj A, Nimbargi RC. Analysis of hematology quality control using six sigma metrics. Indian J Pathol Microbiol 2024; 67: 332-5. doi:10.4103/ijpm.ijpm_352_23. Epub 2023 Nov 9.
Chutsikarinthorn M. The performance evaluation and improving quality management of routine hematology laboratory at BMA General Hospital. J Med Tech Assoc Thailand 2009; 37: 2653-67. (in Thai)
Chantanaskulwong P, Suriya T, Ariyapet S. Quality planning of complete blood count (CBC) by using six sigma and OPSpecs chart in hematology laboratory, Phrae Hospital. PMJCS 2020; 28: 59-75. (in Thai)
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2025 Journal of the Medical Technologist Association of Thailand
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
