Title: Certification of the Catalytic Concentration of Aspartate Transaminase in the Reference Material ERM-AD457/IFCC
Authors: TOUSSAINT BrigitteSCHUMANN GerhardKLAUKE R.MEEUS NeleZELENY ReinhardTRAPMANN StefanieEMONS HendrikSCHIMMEL Heinz
Publisher: OPOCE
Publication Year: 2009
JRC N°: JRC51414
ISBN: 978-92-79-12206-4
ISSN: 1018-5593
Other Identifiers: EUR 23808 EN
OPOCE LA-NA-23808-EN-C
URI: http://publications.jrc.ec.europa.eu/repository/handle/JRC51414
DOI: 10.2787/10322
Type: EUR - Scientific and Technical Research Reports
Abstract: The production and certification of ERM-AD457/IFCC, a new reference material for the enzyme aspartate transaminase (AST) [L-aspartate: 2-oxoglutarate-aminotransferase, EC 2.6.1.1], also called aspartate aminotransferase (ASAT), is described. The certified reference material is lyophilised and should be reconstituted by addition, gravimetrically controlled, of 2 g highly purified water comparable to bi-distilled water. The certified catalytic activity concentration and certified uncertainty of AST in the reconstituted material are (1.74 ± 0.05) µkat/L or (104.6 ± 2.7) U/L (k=2, obtained with the IFCC reference procedure at 37 °C). The material was produced from a human type recombinant AST in E. coli and a buffer containing bovine serum albumin. A first batch of the material was processed, filled into vials (1 mL per vial) and lyophilised. The vials were closed with a stopper and a metal cap. This batch was used as a trial batch to test the lyophilisation process, the homogeneity and the stability of AST in the material. A reconstitution protocol was also developed. Following the positive results obtained on the trial batch, a second batch was produced in the same way. The homogeneity and the stability of this batch were assessed using an In Vitro Diagnostic assay. Then a feasibility study was carried out to characterise the material using a reference procedure from the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC). Twelve expert laboratories participated in the study and familiarised themselves with the protocol. Finally, the characterisation of the material was performed. A good agreement between the results of the 12 laboratories allowed the value assignment of AST in the material in terms of catalytic activity concentration of AST (U/L or µkat/L) in the reconstituted material. The material is aiming to control the IFCC reference procedure for AST at 37 °C. It can also be used to calibrate assays if the commutability of the material with patient samples is demonstrated for these assays.
JRC Institute:Institute for Reference Materials and Measurements

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