Evaluation of Analytical Process Performance by Six Sigma Method

Year 2019, , 177 - 183, 01.09.2019

Dilek İren Emekli Nergiz Zorbozan Zübeyde Erbayraktar

https://doi.org/10.30621/jbachs.2019.732

Abstract

Purpose: Clinical laboratories are responsible for producing reliable, reproducible and accurate test results. Should establish quality in their test analysis and evaluate process performance. Six sigma is a quality management strategy that evaluation of processes. The aim of our study is to evaluate the analytical process performance of routine tests in our laboratory with six sigma method.Methods: Internal quality control IQC data of routine tests in our laboratory were obtained retrospectively. Mean, standard deviation and coefficient of variation CV values of the IQC data were calculated. Process sigma values were calculated using the formula “Total Allowable Error TEa %-Bias% /CV% “. TEa values were determined according to CLIA’88. Sigma value ≤3 low quality, between 3 and 6 good quality and ≥6 was recognized as world class quality.Results: The sigma levels of all the tests we evaluated were >3. Sigma levels of albumin, creatinine, LDL, urea, chloride, total cholesterol, HDL, sodium for IQC 1; albumin, urea, UIBC, chloride, creatinine, potassium, sodium and direct bilirubin for IQC2 were between 3–6. The sigma levels of ALP, ALT, AST, CK, CKMB, iron, UIBC, phosphorus, GGT, glucose, calcium, LDH, magnesium, potassium, total protein, triglyceride, uric acid, amylase, lipase, direct bilirubin, total bilirubin, CRP for IQC 1; ALP, ALT, AST, CK, CK-MB, iron, phosphorus, GGT, glucose, calcium, total cholesterol, HDL, LDL, LDH, magnesium, total protein, triglyceride, uric acid, amylase, lipase, total bilirubin, CRP tests for IQC 2 were ≥6.Conclusion: Six sigma methodology is an effective method for evaluating the analytical process performance of the laboratory. According to the results of our study, our laboratory performance is good or first class

Keywords

six sigma, total allowable error, quality control

References

• Westgard JO. Six sigma quality design and control, 2nd ed. Madison WI. Westgard QC Inc; 2006.
• Zorbozan O, Zorbozan N, Turgay N. Üçüncü basamak sağlık merkezinin parazitoloji laboratuvarında analiz öncesi sürecin kalite belirteçleri ve altı sigma yöntemi ile değerlendirilmesi. Mikrobiyol Bul 2019;53:319–329. [CrossRef]
• CLSI. Developing and using quality indicators for laboratory improvement, 2nd ed. CLSI guideline QMS12. Wayne, PA. Clinical laboratory standards institute; 2019.
• Wolcott J, Schwartz A, Goodman C, editors. Laboratory Medicine a National Status Report. Chapter IV: Quality and the Total Testing Process. 2008. pp.139–195. Available at: https://www.cdc.gov/ labbestpractices/pdfs/2007-status-report-laboratory_medicine_-_a_ national_status_report_from_the_lewin_group_updated_2008-9.pdf
• Coskun A, Inal T, Unsal I, Serteser M. Six sigma as a quality management tool: Evaluation of performance in laboratory medicine. www.intechopen.com 2007;247–262. [CrossRef]
• Coskun A, editor. Quality Management and Six Sigma (ISBN 978-953- 307-130-5). www.sciyo.com. Rijeka: Croatia; 2010.
• Sciacovelli L, Plebani M. The IFCC Working group on laboratory errors and patient safety. Clin Chim Acta 2009;404:79–85. [CrossRef]
• Sciacovelli L, O’Kane M, Skaik YA, et al. Quality ındicators in laboratory medicine: from theory to practice. Preliminary data from the IFCC working group project “Laboratory errors and patient safety”. Clin Chem Lab Med 2011;49:835–844. [CrossRef]
• Demir S. Süreç Performansının Ölçülmesi: Altı Sigma Yöntemi. Aslan D, editör. Klinik laboratuvarlarda analitik kalite yönetimi kursu kitabı. İzmir: Türk Biyokimya Derneği; 2010. pp.83–90.
• Lippi G, Plebani M, Simundic A. Special issue: Quality in laboratory diagnostics: from theory to practice. Biochemia Medica 2010;20:126– 130. [CrossRef]
• Avcı E, Çeken N, Kangal Z, Demir S, İren Emekli D, Zorbozan N. Approach to pre-analytical errors in a public health laboratory. Turk J Biochem 2017;42:59–63. [CrossRef]
• Westgard JO. Managing quality vs. measuring uncertainty in the medical laboratory. Clin Chem Lab Med 2010;48:31–40. [CrossRef] https://doi.org/10.1515/CCLM.2010.024
• Llopis MA, Trujillo G, Llovet MI, et al. Quality indicators and specifications for key analytical-extranalytical processes in the clinical laboratory. Five years’ experience using the six sigma concept. Clin Chem Lab Med 2011;49:463–470. [CrossRef]
• Miller G. Quality Control. In: McPherson R, Pincus M, editors. Henry’s Clinical Diagnosis and Management by Laboratory Methods, 22nd ed. Philadelphia, PA: Suanders; 2011. pp.119–234.
• Nar R, Iren Emekli D. The evaluation of analytical performance of immunoassay tests by using six-sigma method. J Med Biochem 2017;36:301–308. [CrossRef]
• Fraser CG, Kallner A, Kenny D, Hyltoft Petersen P, P. Strategies to set global analytical quality specifications in laboratory medicine. Scand J Clin Lab Invest 1999;59:475–585. [CrossRef]
• Hens K, Berth M, Armbruster D, Westgard S. Sigma metrics used to assess analytical quality of clinical chemistry assays: importance of the allowable total error (TEa) target. Clin Chem Lab Med 2014;52:973– 980. [CrossRef]
• Aslan D, Demir S. Laboratuvar tıbbında altı sigma kalite yönetimi. Turk J Biochem 2005;30:272–278. Available at: http://www.turkjbiochem. com/2005/272_278.pdf
• Aslan D, Sert S, Aybek H, Yılmaztürk G. Klinik laboratuvarlarda toplam laboratuvar performansının değerlendirilmesi: Normalize OPSpec grafikleri, altı sigma ve hasta test sonuçları. Turk J Biochem 2005;30:296–305. Available at: http://www.turkjbiochem. com/2005/296_305.pdf
• Inal T. Preanalitik süreçte altı sigma. Aslan D, editör. Klinik laboratuvarlarda analitik kalite yönetimi kursu kitabı. İzmir: Türk Biyokimya Derneği; 2010. pp.91–94.
• Westgard JO. Control of analytical quality using patient data; section III. In: Tietz NW, Burtis CA, Ashwood AR, Bruns DE, editors. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics, 4th ed. St. Louis: Elsevier Saunders Company; 2006. pp.510–515.
• İnal BB, Usta M, Aral H, Tuhral C, Bilgi PT, Güvenen G. Vitamin B12 ölçümlerinin kısa dönemli analitik performansının değerlendirilmesinde normallerin ortalaması (AON) uygulaması. Turk J Biochem 2010;35:67–71. Available at: http://www.turkjbiochem. com/2010/067-071.pdf
• Kazmierczak SC. Laboratory quality control using patient data to assess analytical performance. Clin Chem Lab Med 2003;41:617–627. [CrossRef]
• Pande PS, Neuman RP, Cavanagh RR. The Six Sigma Way, 1st ed. New York: McGraw Hill; 2000.
• Berte ML. Laboratory Quality Management: A road map. Clin Lab Med 2007;27:771–790. [CrossRef]
• Mao X, Shao J, Zhang B, Wang Y. Evaluating analytical quality in clinical biochemistry laboratory using six sigma. Biochem Med (Zagreb) 2018;28:020904. [CrossRef]
• Afrifa J, Gyekye SA, Owiredu WK, et al. Application of sigma metrics for the assessment of quality control in clinical chemistry laboratory in Ghana: A pilot study. Niger Med J 2015;56:54–58. [CrossRef]
• 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;26:131–135. [CrossRef]
• Nanda SK, Ray L. Quantitative application of sigma metrics in medical biochemistry. J Clin Diagn Res 2013;7:2689–2691. [CrossRef]