DOI: http://dx.doi.org/10.18203/2349-3933.ijam20194155

Application of six sigma metrics and method decision charts in improvising clinical Chemistry laboratory performance enhancement

Kavita Aggarwal, Saurav Patra, Viyatprajna Acharya, Mahesh Agrawal, Sri Krushna Mahapatra

Abstract


Background: Six sigma is a powerful tool which can be used by laboratories for assessing the method quality, optimizing Quality Control (QC) procedure, change the number of rules applied, and frequency of controls run .The aim of this study was to quantify the defects or errors in the analytical phase of laboratory testing by sigma metrics and then represent the sigma value in Method Decision Chart.

Methods: A retrospective study was conducted in a tertiary care hospital in Bhubaneswar, India. The clinical chemistry laboratory has been NABL accredited for the past 5 years and strictly quality checked.  Internal and external quality control data was collected for a period of six months from January - June 2018 for 20 biochemical analytes. Sigma metrics for each parameter was calculated and plotted on method decision chart.

Results: The sigma metrics for level 2 indicated that 6 out of the 20 analytes qualified Six Sigma quality performance. Of these seven analytes failed to meet minimum sigma quality performance with metrics less than three and another seven analytes performance with sigma metrics was between three and six. For level 3, the data collected indicated that seven out of 20 analytes qualified Six Sigma quality performance, six analytes had sigma metrics less than 3 and seven analytes had sigma metrics between 3 and 6.

Conclusion: In our study Sigma value was highest for amylase and lowest for potassium. Use of alternative methods and/ or change of reagents can be done for potassium to bring the sigma value within an acceptable range.


Keywords


Bias, Imprecision, Method decision chart, Quality control, Quality Goal Index, Sigma metrics

Full Text:

PDF

References


Forsman RW. Why is the laboratory an afterthought for managed care organizations? Clin Chem 1996;42(5):813-6.

Westgard JO, Barry PL, Hunt MR, Groth T. A multi-rule Shewhart chart for quality control in clinical chemistry. Clin Chem. 1981;27(3):493-501.

Westgard JO, Westgard SA. The quality of laboratory testing today: an assessment of sigma metrics for analytic quality using performance data from proficiency testing surveys and the CLIA criteria for acceptable performance. Am J Clin Pathol. 2006;125(3):343-54.

Shah S, Saini R, Singh SB, Aggarwal O, Goel AK. Six Sigma Metrics and Quality Control in Clinical Laboratory. Int J Med Res Rev. 2014;28(2):140-9.

Westgard JO, Westgard SA. An assessment of σ metrics for analytic quality using performance data from proficiency testing surveys and the CLIA criteria for acceptable performance. J Vet Diagn Invest. 2008;20:536-44.

Nevalainen D, Berte L, Kraft C, Leigh E, Picaso L, Morgan T. Evaluating laboratory performance on quality indicators with the six sigma scale. Arch Pathol Lab Med. 2000;124(4):516-9.

Mao X, Shao J, Zhang B, Wang Y. Evaluating analytical quality in clinical biochemistry laboratory using Six Sigma. Biochem Med. (Zagreb) 2018;28(2):020904.

Xia Y, Xue H, Yan C, Li B, Zhang SQ, Li M, Ji L. Risk analysis and assessment based on Sigma metrics and intended use. Biochem Med. (Zagreb) 2018;28(2):020707.

Westgard JO. A method evaluation decision chart (MEDx chart) for judging method performance. Clin Lab Sci. 1995;8(5):277-83.

U.S. Department of health and human services. Clinical Laboratory Improvement Amendments of 1988. Final rules and notice. 42 CFR Part 493. Federal Register. 1992;57:7188-288.

Cao S, Qin X. Application of Sigma-metrics in assessing the clinical performance of verified versus non-verified reagents for routine biochemical analytes. Biochem Med (Zagreb). 2018;28(2):020709.

Chakravarthy S, Ramanathan S, Smitha S, Vijayakumar KV, Nallathambi T, Michael S. Phoenix in the lab: The sigma metrics during Chennai’s worst disaster: Monitoring and management of the Quality Management System (QMS). IJPLM. 2017;3(1):OA1.

Singh B, Goswami B, Gupta VK, Chawla R, Mallika V. Application of Sigma Metrics for the Assessment of Quality Assurance in Clinical Biochemistry Laboratory in India: A Pilot Study. Indian J Clin Biochem. 2011;26(2):131-5.

Nanda SK, Ray L. Quantitative application of sigma metrics in medical biochemistry. J Clin Diagn Res. 2013;7(12):2689-91.

Verma M, Dahiya K, Ghalaut VS, Dhupper V. Assessment of quality control system by sigma metrics and quality goal index ratio: A roadmap towards preparation for NABL. World J Methodol. 2018;8(3):44-50.

Adiga US, Preethika A, Swathi K. Sigma metrics in clinical chemistry laboratory - A guide to quality control. Al Ameen J Med Sci. 2015;8(4):281-7.

Lakshman M, Reddy B, Bhulaxmi P, Malathi K, Salma M, Prakasham S. Evaluation of sigma metrics in a Medical Biochemistry lab. IJBR. 2015;6(3):164-71.

Kumar BV, Mohan T. Sigma metrics as a tool for evaluating the performance of internal quality control in a clinical chemistry laboratory. J Lab Physicians. 2018;10(2):194-9.

Adiga US, Preethika A. Sigma metrics of electrolytes-a pilot study. IJRSB. 2015;3(11):33-7.

Schoenmakers CH, Naus AJ, Vermeer HJ, Van Loon D, Steen G. Practical application of Sigma Metrics QC procedures in clinical chemistry. Clin Chem Lab Med. 2011;49(11):1837-43.