The clinical relevance of MOG antibody testing in cerebrospinal fluid.

Myelin oligodendrocyte glycoprotein antibody‐associated disease (MOGAD) is diagnosed by serum MOG‐immunoglobulin G (MOG‐IgG) in association with typical demyelination. 111/1127 patients with paired CSF/serum samples were seropositive for MOG‐IgG. Only 7/1016 (0.7%) seronegative patients had CSF‐restricted MOG‐IgG. While 3/7 patients had longitudinally extensive transverse myelitis, four had a confirmed alternate diagnosis (three multiple sclerosis, one CNS vasculitis). In a national referral setting, CSF‐restricted MOG‐IgG had a low sensitivity (2.63%, 95%CI 0.55–7.50%) and low positive predictive value (1.97%, 95%CI 0.45–8.13%). We strongly recommend serum as the preferred diagnostic biospecimen, and urge caution in the interpretation of CSF‐restricted MOG‐IgG in patients without clinico‐radiological features consistent with MOGAD. [ABSTRACT FROM AUTHOR]