A multi-center study of neurofilament assay reliability and inter-laboratory variability by Gray, E, Oeckl, P, Amador, MDM, Andreasson, U, An, J, Blennow, K, Bowser, R, De Schaepdryver, M, Heslegrave, A, Kuhle, J, Maceski, A, Koel-Simmelink, M, Lamari, F, Lombardi, V, Malaspina, A, Nilsson, I, Poesen, K, Salachas, F, Steinacker, P, Teunissen, CE, Van Damme, P, Zetterberg, H, Ludolph, A, Jeromin, A, Turner, MR, Otto, M