Abstract
Objectives
Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has become a common technique in clinical laboratories in recent years. Because most methods are laboratory-developed tests (LDTs), their reproducibility and quality control (QC) have been controversial. In this study, Westgard Sigma Rules were used to evaluate the analytical performance and establish an individualised internal QC (IQC) strategy for these LDTs.
Methods
Taking the LC-MS/MS LDT method for homocysteine (Hcy) as an example, the ‘desirable specifications’ from the Biological Variation Database were used as quality goals. Based on the external quality assessment (EQA) samples, bias was calculated and the coefficient of variation (CV) was also calculated by IQC measurements for six consecutive months. The analytical performance was evaluated by calculated sigma metrics and an IQC strategy was designed using the Westgard Sigma Rules with run size.
Results
Over 116 days within 6 months, a total of 850 data points were collected for each of IQC 1 and IQC 2. The monthly coefficient of variation CV% was 2.57–4.01%, which was non-significant (p-value: 0.75). The absolute bias% for IQC1 and IQC2 was 1.23 and 1.87%, respectively. The allowable total error (TEa) was selected as 15.5%, Sigma metrics were 4.02 and 4.30, and the analytical performance was ‘Good’. The 13s/22s/R4s/41s multi rules (n=4, r=1) with a run size of 200 samples were suggested for the Hcy IQC scheme. The quality goal index (QGI) values were over 1.2, indicating that trueness needed to be improved.
Conclusions
The analytical performance of the Hcy LC-MS/MS LDT conformed to the Six Sigma rating level, achieving ‘good’ (four Sigma). Clinical practice indicated that calibration bias was the primary factor affecting trueness.
Funding source: Science and Technology Program of Shenyang
Award Identifier / Grant number: 21-173-9-25
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Research funding: Science and Technology Program of Shenyang (21-173-9-25).
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Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission.
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Competing interests: Authors state no conflict of interest.
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Informed consent: Not applicable.
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Ethical approval: Not applicable.
References
1. Jakubowski, H. Homocysteine modification in protein structure/function and human disease. Physiol Rev 2019;99:555–04. https://doi.org/10.1152/physrev.00003.2018.Search in Google Scholar PubMed
2. Christine, CW, Auinger, P, Joslin, A, Yelpaala, Y, Green, R. Vitamin B12 and homocysteine levels predict different outcomes in early parkinson’s Disease. Mov Disord 2018;33:762–70. https://doi.org/10.1002/mds.27301.Search in Google Scholar PubMed
3. Luchsinger, JA, Mayeux, R. Dietary factors and Alzheimer’s disease. Lancet Neurol 2004;3:579–87. https://doi.org/10.1016/s1474-4422(04)00878-6.Search in Google Scholar PubMed
4. Jensen, MK, Bertoia, ML, Cahill, LE, Agarwal, I, Rimm, EB, Mukamal, KJ. Novel metabolic biomarkers of cardiovascular disease. Nat Rev Endocrinol 2014;10:659–72. https://doi.org/10.1038/nrendo.2014.155.Search in Google Scholar PubMed
5. Faeh, D, Chiolero, A, Paccaud, F. Homocysteine as a risk factor for cardiovascular disease: should we (still) worry about? Swiss Med Wkly 2006;136:745–56. https://doi.org/10.2006/47/smw-11283.Search in Google Scholar
6. Lin, H, Cai, Z, Zhang, Q, Yang, W, Yan, J, Han, L, et al.. Performances evaluation of four systems for homocysteine determination by LC-MS/MS reference method. Clin Lab 2021;67:697–06. https://doi.org/10.7754/clin.lab.2020.200501.Search in Google Scholar PubMed
7. Armbruster, D, Miller, RR. The Joint Committee for Traceability in Laboratory Medicine (JCTLM): a global approach to promote the standardisation of clinical laboratory test results. Clin Biochem Rev 2007;28:105–13.Search in Google Scholar
8. Lynch, KL. Accreditation and quality assurance for clinical liquid chromatography-mass spectrometry laboratories. Clin Lab Med 2018;38:515–26. https://doi.org/10.1016/j.cll.2018.05.002.Search in Google Scholar PubMed
9. Westgard, JO, Westgard, SA. Establishing evidence-based statistical quality control practices. Am J Clin Pathol 2019;151:364–70. https://doi.org/10.1093/ajcp/aqy158.Search in Google Scholar PubMed
10. Nar, R, Emekli, DI. The evaluation of analytical performance of immunoassay tests by using six-sigma method. J Med Biochem 2017;36:301–8. https://doi.org/10.1515/jomb-2017-0026.Search in Google Scholar PubMed PubMed Central
11. Liu, Q, Bian, G, Chen, X, Han, J, Chen, Y, Wang, M, et al.. Application of a six sigma model to evaluate the analytical performance of urinary biochemical analytes and design a risk-based statistical quality control strategy for these assays: a multicenter study. J Clin Lab Anal 2021;35:e24059. https://doi.org/10.1002/jcla.24059.Search in Google Scholar PubMed PubMed Central
12. WESTGARD, QC. Desirable biological variation database specifications; 2019. Available from: https://www.westgard.com/biodatabase1.htm [Accessed 20 Jul 2022].Search in Google Scholar
13. Li, Z, Liu, M, Chen, C, Pan, Y, Cui, X, Sun, J, et al.. Simultaneous determination of serum homocysteine, cysteine, and methionine in patients with schizophrenia by liquid chromatography-tandem mass spectrometry. Biomed Chromatogr 2022;36:e5366. https://doi.org/10.1002/bmc.5366.Search in Google Scholar PubMed
14. China, NCCL. Quality management tools; 2020. Available from: http://a.clinet.com.cn/SigmaPV/Index.aspx [Accessed 16 Jul 2022].Search in Google Scholar
15. Wang, H, Ma, Y, Shan, X. Evaluating the analytical quality control of urinary albumin measurements using sigma metrics. Clin Biochem 2019;73:109–11. https://doi.org/10.1016/j.clinbiochem.2019.07.011.Search in Google Scholar PubMed
16. Köcher, T, Pichler, P, Swart, R, Mechtler, K. Quality control in LC-MS/MS. Proteomics 2011;11:1026–30. https://doi.org/10.1002/pmic.201000578.Search in Google Scholar PubMed
17. American Association for Clinical Chemistry. No guarantees: how standardization and harmonization ensure LC-MS/MS assays fulfill their potential; 2016. Available from: https://www.aacc.org/cln/articles/2016/november/no-guarantees-how-standardization-and-harmonization-ensure-lc-msms-assays-fulfill-their-potential [Accessed 15 Jul 2022].Search in Google Scholar
18. NIST. SRM 1950 metabolites in frozen human plasma; 2020. Available from: https://www-s.nist.gov/srmors/certificates/1950.pdf [Accessed 20 Jul 2022].Search in Google Scholar
19. NIST. SRM1955 homocysteine and folate in frozen human serum; 2015. Available from: https://www-s.nist.gov/srmors/certificates/1955.pdf [Accessed 20 Jul 2022].Search in Google Scholar
20. Solsvik, AE, Kristoffersen, AH, Sandberg, S, Gidske, G, Stavelin, AV, Eikeland, J, et al.. A national surveillance program for evaluating new reagent lots in medical laboratories. Clin Chem Lab Med 2022;60:351–60. https://doi.org/10.1515/cclm-2021-1262.Search in Google Scholar PubMed
21. van Schrojenstein Lantman, M, Çubukçu, HC, Boursier, G, Panteghini, M, Bernabeu-Andreu, FA, Milinkovic, N, et al.. An approach for determining allowable between reagent lot variation. Clin Chem Lab Med 2022;60:681–8. https://doi.org/10.1515/cclm-2022-0083.Search in Google Scholar PubMed
Supplementary Material
The online version of this article offers supplementary material (https://doi.org/10.1515/cclm-2022-0805).
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