TY - JOUR T1 - Multicentre comparison of a diagnostic assay: aquaporin-4 antibodies in neuromyelitis optica JF - Journal of Neurology, Neurosurgery & Psychiatry JO - J Neurol Neurosurg Psychiatry SP - 1005 LP - 1015 DO - 10.1136/jnnp-2015-312601 VL - 87 IS - 9 AU - Patrick Waters AU - Markus Reindl AU - Albert Saiz AU - Kathrin Schanda AU - Friederike Tuller AU - Vlastimil Kral AU - Petra Nytrova AU - Ondrej Sobek AU - Helle Hvilsted Nielsen AU - Torben Barington AU - Søren T Lillevang AU - Zsolt Illes AU - Kristin Rentzsch AU - Achim Berthele AU - Tímea Berki AU - Letizia Granieri AU - Antonio Bertolotto AU - Bruno Giometto AU - Luigi Zuliani AU - Dörte Hamann AU - E Daniëlle van Pelt AU - Rogier Hintzen AU - Romana Höftberger AU - Carme Costa AU - Manuel Comabella AU - Xavier Montalban AU - Mar Tintoré AU - Aksel Siva AU - Ayse Altintas AU - Günnur Deniz AU - Mark Woodhall AU - Jacqueline Palace AU - Friedemann Paul AU - Hans-Peter Hartung AU - Orhan Aktas AU - Sven Jarius AU - Brigitte Wildemann AU - Christian Vedeler AU - Anne Ruiz AU - M Isabel Leite AU - Peter Trillenberg AU - Monika Probst AU - Sandra Saschenbrecker AU - Angela Vincent AU - Romain Marignier Y1 - 2016/09/01 UR - http://jnnp.bmj.com/content/87/9/1005.abstract N2 - Objective Antibodies to cell surface central nervous system proteins help to diagnose conditions which often respond to immunotherapies. The assessment of antibody assays needs to reflect their clinical utility. We report the results of a multicentre study of aquaporin (AQP) 4 antibody (AQP4-Ab) assays in neuromyelitis optica spectrum disorders (NMOSD).Methods Coded samples from patients with neuromyelitis optica (NMO) or NMOSD (101) and controls (92) were tested at 15 European diagnostic centres using 21 assays including live (n=3) or fixed cell-based assays (n=10), flow cytometry (n=4), immunohistochemistry (n=3) and ELISA (n=1).Results Results of tests on 92 controls identified 12assays as highly specific (0–1 false-positive results). 32 samples from 50 (64%) NMO sera and 34 from 51 (67%) NMOSD sera were positive on at least two of the 12 highly specific assays, leaving 35 patients with seronegative NMO/spectrum disorder (SD). On the basis of a combination of clinical phenotype and the highly specific assays, 66 AQP4-Ab seropositive samples were used to establish the sensitivities (51.5–100%) of all 21 assays. The specificities (85.8–100%) were based on 92 control samples and 35 seronegative NMO/SD patient samples.Conclusions The cell-based assays were most sensitive and specific overall, but immunohistochemistry or flow cytometry could be equally accurate in specialist centres. Since patients with AQP4-Ab negative NMO/SD require different management, the use of both appropriate control samples and defined seronegative NMOSD samples is essential to evaluate these assays in a clinically meaningful way. The process described here can be applied to the evaluation of other antibody assays in the newly evolving field of autoimmune neurology. ER -