David M Bunk1, Michael J Welch. 1. Analytical Chemistry Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA. david.bunk@nist.gov
Abstract
BACKGROUND: To address the continuing need for the standardization of clinical human cardiac troponin I (cTnI) assays, NIST, with the assistance of the AACC/IFCC Cardiac Troponin I Standardization Committee, has developed a new certified reference material, Standard Reference Material (SRM) 2921: Human Cardiac Troponin Complex. METHODS: The concentration of cTnI in SRM 2921 was determined through a combination of reversed-phase liquid chromatography (LC) with ultraviolet detection and amino acid analysis. Characterization of the intact troponin subunits was accomplished through reversed-phase LC coupled with mass spectrometry. Posttranslational modifications to the cTnI in SRM 2921 were investigated by combining proteolytic digestion with matrix-assisted laser desorption/ionization mass spectrometry. Additionally, reference concentration values for cTnT and cTnC were also determined. RESULTS: The concentration of human cTnI in SRM 2921 is 31.2 (1.4) mg/L (where 1.4 mg/L is the uncertainty at a 95% level of confidence), as certified through a method that provides traceability to the International System of Units (SI). Reference concentration values of the cTnT and cTnC subunits were determined to be 36.9 (3.8) mg/L and 24.2 (1.3) mg/L, respectively. CONCLUSIONS: This first cTnI reference material should provide SI traceability to clinical cTnI assays once commutability has been validated, and could assist in the international harmonization of cTnI assays as a tool for understanding the underlying causes of interassay variability.
BACKGROUND: To address the continuing need for the standardization of clinical humancardiac troponin I (cTnI) assays, NIST, with the assistance of the AACC/IFCC Cardiac Troponin I Standardization Committee, has developed a new certified reference material, Standard Reference Material (SRM) 2921: Human Cardiac Troponin Complex. METHODS: The concentration of cTnI in SRM 2921 was determined through a combination of reversed-phase liquid chromatography (LC) with ultraviolet detection and amino acid analysis. Characterization of the intact troponin subunits was accomplished through reversed-phase LC coupled with mass spectrometry. Posttranslational modifications to the cTnI in SRM 2921 were investigated by combining proteolytic digestion with matrix-assisted laser desorption/ionization mass spectrometry. Additionally, reference concentration values for cTnT and cTnC were also determined. RESULTS: The concentration of humancTnI in SRM 2921 is 31.2 (1.4) mg/L (where 1.4 mg/L is the uncertainty at a 95% level of confidence), as certified through a method that provides traceability to the International System of Units (SI). Reference concentration values of the cTnT and cTnC subunits were determined to be 36.9 (3.8) mg/L and 24.2 (1.3) mg/L, respectively. CONCLUSIONS: This first cTnI reference material should provide SI traceability to clinical cTnI assays once commutability has been validated, and could assist in the international harmonization of cTnI assays as a tool for understanding the underlying causes of interassay variability.
Authors: Niklas Mattsson; Ulf Andreasson; Staffan Persson; Hiroyuki Arai; Sat Dev Batish; Sergio Bernardini; Luisella Bocchio-Chiavetto; Marinus A Blankenstein; Maria C Carrillo; Sonia Chalbot; Els Coart; Davide Chiasserini; Neal Cutler; Gunilla Dahlfors; Stefan Duller; Anne M Fagan; Orestes Forlenza; Giovanni B Frisoni; Douglas Galasko; Daniela Galimberti; Harald Hampel; Aase Handberg; Michael T Heneka; Adrianna Z Herskovits; Sanna-Kaisa Herukka; David M Holtzman; Christian Humpel; Bradley T Hyman; Khalid Iqbal; Mathias Jucker; Stephan A Kaeser; Elmar Kaiser; Elisabeth Kapaki; Daniel Kidd; Peter Klivenyi; Cindy S Knudsen; Markus P Kummer; James Lui; Albert Lladó; Piotr Lewczuk; Qiao-Xin Li; Ralph Martins; Colin Masters; John McAuliffe; Marc Mercken; Abhay Moghekar; José Luis Molinuevo; Thomas J Montine; William Nowatzke; Richard O'Brien; Markus Otto; George P Paraskevas; Lucilla Parnetti; Ronald C Petersen; David Prvulovic; Herman P M de Reus; Robert A Rissman; Elio Scarpini; Alessandro Stefani; Hilkka Soininen; Johannes Schröder; Leslie M Shaw; Anders Skinningsrud; Brith Skrogstad; Annette Spreer; Leda Talib; Charlotte Teunissen; John Q Trojanowski; Hayrettin Tumani; Robert M Umek; Bianca Van Broeck; Hugo Vanderstichele; Laszlo Vecsei; Marcel M Verbeek; Manfred Windisch; Jing Zhang; Henrik Zetterberg; Kaj Blennow Journal: Alzheimers Dement Date: 2011-07 Impact factor: 21.566