apfcbAPFCB eNewscoAPFCB News Volume 5, Issue 2MultidisciplinaryEnglishJuly-Dec, 2026NNY2026099ArticlesMaintaining and Improving Sigma Performance on VITROS 5600: A Positive QC Story from Yashoda Hospitals, SecunderabadEnglishY3944Dr MadhaviDevalarajuEnglishNDr. RajkumarRathodEnglishY10.62772/APFCB-News.2026.5201Background: Sigma metrics (σ) guide risk-based quality control (QC) by integrating bias, imprecision and TEa. We summarize how two analyzers maintained their Sigma bands over time and where analytes moved up a band, following targeted QC interventions. Methods: Average σ was compiled at QC levels (L1/L2/L3 wherever is applicable) and categorized into >6 sigma,>5 to4 to 3 to 5 σ for Clinical Chemistry (50.0%→73.1%). Instrument 56000582 (backup) showed improved >5 σ share in Immunoassay (57.1%→71.4%), with Prolactin moving up into ≥5 σ while other analytes maintained high bands. Conclusions: Enhanced QC preparation/handling/storage, calibration, and lot management supported maintenance within bands sustained Sigma performance and band-up improvements without emphasizing declines.Englishhttps://www.apfcb.org/APFCB_News/abstract?id=49References16191. Clinical Laboratory Improvement Amendments (CLIA). 2024 CLIA requirements [Internet]. Available from: https://westgard.com/clia-and-quality-regulation-requirements/qualityrequirements/2024-clia-requirements.html [accessed April 2026]. 2. Ricos C, Alvarez V, Cava F, et al. Biological variation database [Internet]. Available from: https://www.westgard.com/biodatabase1.htm [accessed April 2026]. 3. College of American Pathologists (CAP). Proficiency Testing Standards and Acceptable Limits; 2024. 4. Royal College of Pathologists of Australasia (RCPA). Allowable limits of performance for biochemistry tests [https://dataanalysis.rcpaqap.com.au/analytical-performancespecifications/]. [accessed April 2026]. 5. A Kirsch, R Lesiv, Ortho Clinical Diagnostics Rochester, New York;M Barba Laboratory Diagnostics Consulting, Atlanta, Georgia. Comparative Study of Six SigmaAssay Performance on VITROSand;reg; Systems. AACC Annual Meeting and;amp; Clinical Lab Expo July 31and;ndash;August 4, 2016. 6. Lakshman M, Reddy BR, Bhukani P, Malathi K, Salma M. Evaluation of sigma metrics in a medical biochemistry lab. International Journal of Biomedical Research 2015; 6(03): 164-171. 7. Chakravarthy S, Ramanathan S, Smitha S, Vijayakumar KV, Nallathambi T, Selvaraj M. Phoenix in the lab: The sigma metrics during Chennaiand;rsquo;s worst disaster: Monitoring and management of the Quality Management System (QMS). APFCB News. 2026;5(1). 8. B. Vinodh Kumar, Thuthi Mohan. Sigma metrics as a tool for evaluating the performance of internal quality control in a clinical chemistry laboratory. Journal of Laboratory Physicians - Volume 10, Issue 2, April-June 2018 199 9. Nibedita Sarma, Subhosmito Chakraborty. Effectiveness of six sigma score analysis of clinical biochemistry parameters in a newly installed automated analyzerand;ndash; Retrospective analysis in a tertiary cancer care centre. International Journal of Clinical Biochemistry and Research 2023;10(1):81and;ndash;86 10. Pinki Mayankkumar Joshi, Urmi Kalrav Patel1. Performance evaluation of routine analytes using six sigma principle in a stand-alone clinical laboratory. International Journal of Clinical Biochemistry and Research 2022;9(2):127and;ndash;134 11. Bais B, Singh K, Tripathi V, Kheirnar C. Sigma performance evaluations for clinical chemistry and immunoassays in a tertiary care hospital laboratory based on Clinical Laboratory Improvement Amendments (CLIA) 1988 and 2024 guidelines. Int J Clin Biochem Res. 2024;11(2):129and;ndash;141.