Abstract
The goal of External Quality Assessment (EQA) schemes is to ensure that results obtained on a particular specimen in a given clinical laboratory are compatible with those obtained by other laboratories on the same specimen. Serum protein electrophoresis is a laboratory test consisting of five fractions (albumin, α1, α2, β and γ globulins), which sum up to 100% of total proteins. So far, in EQA schemes the five fractions have been analyzed separately as for ordinary tests like glucose or cholesterol. This approach does not consider the fractions as a whole and the linear relationship between them. A statistical approach has been developed to analyze EQA electrophoresis results from a global standpoint by using robust multivariate method to eliminate the effect of outlying profiles. As illustrated on electrophoretic data from the Belgian EQA scheme, the novel approach improves the detection of poor performing laboratories. The method will be implemented in the Belgian EQA scheme on a routine basis.
Similar content being viewed by others
References
Albert A, De Moor G, Libeer JC (1998) Clin Chim Acta 270:43–54. doi:10.1016/S0009–8981(97)00234-9
Tietz W (ed) (1976) Fundamentals of clinical chemistry. W.B. Saunders Company, Philadelphia, pp 127–134
Petrini C, Alessio MG, Scapellato L, Brambilla S, Franzini C (1999) Clin Chem Lab Med 37:975–980. doi:10.1515/CCLM.1999.144
Bossuyt X, Lissoir B, Mariën G, Maisin D, Vunckx J, Blanckaert N, Wallemacq P (2003) Clin Chem Lab Med 41:704–710. doi:10.1515/CCLM.2003.107
Bossuyt X, Schiettekatte G, Bogaerts A, Blankaert N (1998) Clin Chem 44:749–759
Albert A (1997) Biocybern Biomed Eng 17:7–23
Libeer JC (1993) External quality assessment in clinical laboratories. European perspectives: today and tomorrow. Higher Education Doctoral Thesis, Antwerpen
Morrison DF (2004) Multivariate statistical methods. McGraw-Hill, Auckland
Chatfield C, Collins AJ (1980) Introduction to multivariate analysis. Chapman & Hall, London
Albert A, Harris EK (1987) Multivariate interpretation of clinical laboratory data. Dekker, New York
Rousseeuw PJ (1985) Multivariate estimation with high breakdown point. In: Grossmann W, Pflug G, Vincze I, Wertz W (eds) Mathematical statistics and applications, vol B. Reidel, Dordrecht, pp 283–297
Rousseeuw PJ, van Driessen K (1999) Technometrics 41:212–223. doi:10.2307/1270566
Statistical Analysis System (2006) SAS Institute Inc., Cary, North Carolina
S-PLUS Statistical Software (2006) Insightful Corporation, Seattle, Washington
Ricós C, Baadenhuijsen H, Libeer JC, Hyltoft Petersen P, Stöckl D, Thienpont L, Fraser CG (1996) Eur J Clin Chem Clin Biochem 34:159–165
Ricós C, Alvarez V, Cava F, García-Lario JV, Hernández A, Jiménez CV, Minchinela J, Perich C, Simón M (1999) Scand J Clin Lab Invest 59:491–500
Acknowledgments
This study was supported by a research grant from the Scientific Institute of Public Health—Louis Pasteur (Federal Public Service of Social Security, Public Health and Environment), Brussels, Belgium.
Author information
Authors and Affiliations
Corresponding author
Appendices
Appendix 1
Table 5 displays the dataset that was used to illustrate the new methodology.
Appendix 2
Calculation of the mean, variance and covariances of the fraction omitted from the electrophoretic profile.
Let M i be the mean of x i and S ij the covariance between x i and x j (i, j = 1,...,4).
From the formula x 5 = 100−(x 1 + x 2 + x 3 + x 4), it can be shown that:
As an illustration, from Table 4, we have
Rights and permissions
About this article
Cite this article
Zhang, L., Van Campenhout, C., Devleeschouwer, N. et al. Statistical analysis of serum protein electrophoresis results in External Quality Assessment schemes. Accred Qual Assur 13, 149–155 (2008). https://doi.org/10.1007/s00769-008-0388-4
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00769-008-0388-4