Neurofilament ELISA validation
Axel Petzold, Ayse Altintas, Laura Andreoni, Ales Bartos, Achim Berthele, Marinus A Blankenstein, Luc Buee, Massimiliano Castellazzi, Sabine Cepok, Manuel Comabella, Cris S Constantinescu, Florian Deisenhammer, Gunnur Deniz, Gaye Erten, Mercedes Espiño, Enrico Fainardi, Diego Franciotta, Mark S Freedman, Vilmantas Giedraitis, Nils Erik Gilhus, Gavin Giovannoni, Andrzej Glabinski, Pawel Grieb, Hans-Peter Hartung, Bernhard Hemmer, Sanna-Kaisa Herukka, Rogier Hintzen, Martin Ingelsson, Samuel Jackson, Steve Jacobsen, Naghmeh Jafari, Marcin Jalosinski, Sven Jarius, Elisabeth Kapaki, Bernd C Kieseier, Marleen J A Koel-Simmelink, Johannes Kornhuber, Jens Kuhle, Jacek Kurzepa, Patrice H Lalive, Lars Lannfelt, Vera Lehmensiek, Piotr Lewczuk, Paolo Livrea, Fabiana Marnetto, Davide Martino, Til Menge, Niklas Norgren, Eva Papuć, George P Paraskevas, Tuula Pirttilä, Cecília Rajda, Konrad Rejdak, Jan Ricny, Daniela Ripova, Lars Rosengren, Maddalena Ruggieri, Susanna Schraen, Gerry Shaw, Christian Sindic, Aksel Siva, Torgny Stigbrand, Iva Stonebridge, Baris Topcular, Maria Trojano, Hayrettin Tumani, Harry A M Twaalfhoven, László Vécsei, Vincent Van Pesch, Hugo Vanderstichele, Christian Vedeler, Marcel M Verbeek, Luisa Maria Villar, Robert Weissert, Brigitte Wildemann, Cui Yang, Karen Yao, Charlotte E Teunissen, Axel Petzold, Ayse Altintas, Laura Andreoni, Ales Bartos, Achim Berthele, Marinus A Blankenstein, Luc Buee, Massimiliano Castellazzi, Sabine Cepok, Manuel Comabella, Cris S Constantinescu, Florian Deisenhammer, Gunnur Deniz, Gaye Erten, Mercedes Espiño, Enrico Fainardi, Diego Franciotta, Mark S Freedman, Vilmantas Giedraitis, Nils Erik Gilhus, Gavin Giovannoni, Andrzej Glabinski, Pawel Grieb, Hans-Peter Hartung, Bernhard Hemmer, Sanna-Kaisa Herukka, Rogier Hintzen, Martin Ingelsson, Samuel Jackson, Steve Jacobsen, Naghmeh Jafari, Marcin Jalosinski, Sven Jarius, Elisabeth Kapaki, Bernd C Kieseier, Marleen J A Koel-Simmelink, Johannes Kornhuber, Jens Kuhle, Jacek Kurzepa, Patrice H Lalive, Lars Lannfelt, Vera Lehmensiek, Piotr Lewczuk, Paolo Livrea, Fabiana Marnetto, Davide Martino, Til Menge, Niklas Norgren, Eva Papuć, George P Paraskevas, Tuula Pirttilä, Cecília Rajda, Konrad Rejdak, Jan Ricny, Daniela Ripova, Lars Rosengren, Maddalena Ruggieri, Susanna Schraen, Gerry Shaw, Christian Sindic, Aksel Siva, Torgny Stigbrand, Iva Stonebridge, Baris Topcular, Maria Trojano, Hayrettin Tumani, Harry A M Twaalfhoven, László Vécsei, Vincent Van Pesch, Hugo Vanderstichele, Christian Vedeler, Marcel M Verbeek, Luisa Maria Villar, Robert Weissert, Brigitte Wildemann, Cui Yang, Karen Yao, Charlotte E Teunissen
Abstract
Background: Neurofilament proteins (Nf) are highly specific biomarkers for neuronal death and axonal degeneration. As these markers become more widely used, an inter-laboratory validation study is required to identify assay criteria for high quality performance.
Methods: The UmanDiagnostics NF-light (R)enzyme-linked immunoabsorbent assays (ELISA) for the neurofilament light chain (NfL, 68kDa) was used to test the intra-assay and inter-laboratory coefficient of variation (CV) between 35 laboratories worldwide on 15 cerebrospinal fluid (CSF) samples. Critical factors, such as sample transport and storage, analytical delays, reaction temperature and time, the laboratories' accuracy and preparation of standards were documented and used for the statistical analyses.
Results: The intra-laboratory CV averaged 3.3% and the inter-laboratory CV 59%. The results from the test laboratories correlated with those from the reference laboratory (R=0.60, p<0.0001). Correcting for critical factors improved the strength of the correlation. Differences in the accuracy of standard preparation were identified as the most critical factor. Correcting for the error introduced by variation in the protein standards improved the correlation to R=0.98, p<0.0001 with an averaged inter-laboratory CV of 14%. The corrected overall inter-rater agreement was subtantial (0.6) according to Fleiss' multi-rater kappa and Gwet's AC1 statistics.
Conclusion: This multi-center validation study identified the lack of preparation of accurate and consistent protein standards as the main reason for a poor inter-laboratory CV. This issue is also relevant to other protein biomarkers based on this type of assay and will need to be solved in order to achieve an acceptable level of analytical accuracy. The raw data of this study is available online.
Copyright 2009 Elsevier B.V. All rights reserved.
Source: PubMed