Clinical utility of testing AQP4-IgG in CSF

Abstract

Objective: To define, using assays of optimized sensitivity and specificity, the most informative specimen type for aquaporin-4 immunoglobulin G (AQP4-IgG) detection. Methods: Results were reviewed from longitudinal service testing for AQP4-IgG among speci-mens submitted to the Mayo Clinic Neuroimmunology Laboratory from 101,065 individual patients. Paired samples of serum/CSF were tested from 616 patients, using M1-AQP4-transfected cell-based assays (both fixed AQP4-CBA Euroimmun kit [commercial CBA] and live in-house flow cytometry [FACS]). Sensitivities were compared for 58 time-matched paired speci-mens (drawn #30 days apart) from patients with neuromyelitis optica (NMO) or high-risk patients. Results: The frequency of CSF submission as sole initial specimen was 1 in 50 in 2007 and 1 in 5