Towards quality assurance in the determination of lysosomal enzymes

• Verfasst von: Lukacs, Zoltan [VerfasserIn]
• Verfasst von: Keil, A. [VerfasserIn]
• Verfasst von: Peters, Verena [VerfasserIn]
• Verfasst von: Kohlschütter, A. [VerfasserIn]
• Verfasst von: Hoffmann, Georg F. [VerfasserIn]
• Verfasst von: Cantz, Michael [VerfasserIn]
• Verfasst von: Kopitz, Jürgen [VerfasserIn]
• Titel: Towards quality assurance in the determination of lysosomal enzymes
• Titelzusatz: a two-centre study
• Verf.angabe: Z. Lukacs, A. Keil, V. Peters, A. Kohlschütter, G.F. Hoffmann, M. Cantz, J. Kopitz
• Jahr: 2003
• Umfang: 11 S.
• Teil: volume:26
• Teil: year:2003
• Teil: number:6
• Teil: pages:571-581
• Teil: extent:11
• Fussnoten: This revised version was published online in August 2006 with corrections to the cover date ; Gesehen am 21.12.2020
• Titel Quelle: Enthalten in: Journal of inherited metabolic disease
• Ort Quelle: Hoboken, NJ : Wiley, 1978
• Jahr Quelle: 2003
• Band/Heft Quelle: 26(2003), 6, Seite 571-581
• ISSN Quelle: 1573-2665
• DOI: doi:10.1023/A:1025904132569
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1743365519

Abstract

The definitive diagnosis of lysosomal storage disorders depends on the determination of enzymatic activities in cells, tissues or body fluids. At present, neither an evaluation of the different methods nor an interlaboratory quality assurance scheme is available. We have therefore determined the activities of total hexosaminidase, hexosaminidase A and β-galactosidase in the same samples (n=15) at two metabolic centres in Germany. Three different enzymatic methods were employed, two of which were based on leukocytes as enzyme source and one on dried blood spots. The results obtained by the two different methods using leukocytes proved comparable. In contrast, assays with dried blood spots showed poor correlation with results from leukocytes, possibly because enzymatic activity in dried blood is mainly derived from soluble plasma proteins. Nevertheless, accurate detection of a true enzyme deficiency was also possible in dried blood spots. All enzymes were highly stable when mailed frozen (recovery 98-120%). Enzymatic activities in dried blood samples were also stable at room temperature and were not affected even by exposure to elevated temperatures (50°C for 3h). Dried blood seems to be especially well suited for mailing from distant healthcare facilities, although more accurate results can be expected from leukocytes. In summary, comparability and pitfalls within a lysosomal quality assurance programme were evaluated.