Accessible Requires Authentication Published by De Gruyter August 11, 2015

Patient pools and the use of “patient means” are valuable tools in quality control illustrated by a bone-specific alkaline phosphatase assay

Maja Hinge, Erik D. Lund, Ivan Brandslund, Torben Plesner and Jonna S. Madsen

Abstract

Background: Quality control (QC) is an essential part of clinical biochemistry to ensure that laboratory test results are reliable and correct. Those tests without a defined reference method constitute a special challenge, as is the case with bone-specific alkaline phosphatase (BAP).

Methods and Results: The present study reports an example where a shift in a BAP assay was detected by use of a patient pool and supported by a retrospective calculation of “patient mean”, while the external QC and specific assay control material were unaffected by the shift.

Conclusions: Patient pools and the use of patient means remain a useful and inexpensive procedure for internal QC.


Corresponding author: Jonna S. Madsen, Department of Clinical Immunology and Biochemistry, Lillebaelt Hospital, Kabbeltoft 25, 7100 Vejle, Denmark; and Institute of Regional Health Research, University of Southern Denmark, Odense, Denmark, Phone: +45 79406501; E-mail:

Acknowledgments

We would like to thank Liselotte Bjerregård Lauersen for her attentiveness in the laboratory work and for recognizing the steady increase in the results of BAP in the PP.

Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.

Research funding: None declared.

Employment or leadership: None declared.

Honorarium: None declared.

Competing interests: The funding organization(s) played no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the report for publication.

References

1. Ismail AA, Walker PL, Barth JH, Lewandowski KC, Jones R, Burr WA. Wrong biochemistry results: two case reports and observational study in 5310 patients on potentially misleading thyroid-stimulating hormone and gonadotropin immunoassay results. Clin Chem 2002;48:2023–9. Search in Google Scholar

2. Lapworth R, Teal TK. Laboratory blunders revisited. Ann Clin Biochem 1994;31:78–84. Search in Google Scholar

3. Witte DL, VanNess SA, Angstadt DS, Pennell BJ. Errors, mistakes, blunders, outliers, or unacceptable results: how many? Clin Chem 1997;43:1352–6. Search in Google Scholar

4. Vasikaran S, Eastell R, Bruyere O, Foldes AJ, Garnero P, Griesmacher A, et al. Markers of bone turnover for the prediction of fracture risk and monitoring of osteoporosis treatment: a need for international reference standards. Osteoporos Int 2011;22:391–420. Search in Google Scholar

5. Cavalier E, Souberbielle JC, Gadisseur R, Dubois B, Krzesinski JM, Delanaye P. Inter-method variability in bone alkaline phosphatase measurement: clinical impact on the management of dialysis patients. Clin Biochem 2014;47:1227–30. Search in Google Scholar

6. Bowers GN, Burnett RW, McComb RB. Preparation and use of human serum control materials for monitoring precision in clinical chemistry. Clin Chem 1975;21:1830–6. Search in Google Scholar

7. ISO 15189:2012(E) Medical laboratories – Requirements for quality and competence. ISO: Geneva, 2012. Search in Google Scholar

8. Henriksen GM, Pedersen MM, Norgaard I, Blom M, Blou L, Blaabjerg O, et al. Minimally processed fresh frozen human reference sera: preparation, testing, and application to international external quality assurance. Scand J Clin Lab Invest 2004;64:293–308. Search in Google Scholar

9. Broyles DL, Nielsen RG, Bussett EM, Lu WD, Mizrahi IA, Nunnelly PA, et al. Analytical and clinical performance characteristics of Tandem-MP Ostase, a new immunoassay for serum bone alkaline phosphatase. Clin Chem 1998;44:2139–47. Search in Google Scholar

10. Brinc D, Chan MK, Venner AA, Pasic MD, Colantonio D, Kyriakopolou L, et al. Long-term stability of biochemical markers in pediatric serum specimens stored at -80 degrees C: a CALIPER Substudy. Clin Biochem 2012;45:816–26. Search in Google Scholar

11. Kazmierczak SC. Laboratory quality control: using patient data to assess analytical performance. Clin Chem Lab Med 2003;41:617–27. Search in Google Scholar

12. Van Houcke SK, Stepman HC, Thienpont LM, Fiers T, Stove V, Couck P, et al. Long-term stability of laboratory tests and practical implications for quality management. Clin Chem Lab Med 2013;51:1227–31. Search in Google Scholar

13. Wilson A, Roberts WL, Pavlov I, Fontenot J, Jackson B. Patient result median monitoring for clinical laboratory quality control. Clin Chim Acta 2011;412:1441–6. Search in Google Scholar

14. Lott JA, Smith DA, Mitchell LC, Moeschberger ML. Use of medians and “average of normals” of patients’ data for assessment of long-term analytical stability. Clin Chem 1996;42:888–92. Search in Google Scholar

15. Stepman HC, Stöckl D, Stove V, Fiers T, Couck P, Gorus F, et al. Long-term stability of clinical laboratory data: sodium as benchmark. Clin Chem 2011;57:1616–7. Search in Google Scholar

16. Jørgensen LM, Hansen SI, Petersen PH, Sölétormos G. Median of patient results astool for assessment of analytical stability. Clin Chim Acta 2015;446:186–91. Search in Google Scholar

Received: 2015-3-31
Accepted: 2015-7-8
Published Online: 2015-8-11
Published in Print: 2016-3-1

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