MOG-IgG Detection Guidelines

Assay Methodology

The most specific serum test for MOG is a cell-based assay (CBA) using full-length human MOG as the target antigen with Fc-specific (or IgG1-specific) secondary antibodies, which represents the current gold standard for MOG-IgG detection 1
Cell-based assays are the only recommended approach for MOG antibody testing, with specific technical requirements 1, 2, 3
Must employ full-length human MOG as the target antigen (not peptides or denatured protein) 4
Fc-specific or IgG1-specific secondary antibodies are highly recommended to avoid cross-reactivity with IgM and IgA antibodies 1

Serum is the specimen of choice for MOG-IgG testing 1, 5, 2
MOG-IgG is produced mostly extrathecally, resulting in higher serum titers than CSF 1
Shipment at 4°C or on dry ice is advisable if samples don't arrive within 1-2 days 1

Test for MOG-IgG only 1, 5, 2
MOG-IgM and MOG-IgA testing is currently NOT recommended - clinical relevance of isolated MOG-IgM or -IgA results is unknown 5

MOG-IgG concentrations are disease-activity dependent 1, 6, 3
Higher concentrations during acute attacks than remission 4
Lower concentrations while on immunosuppression 4
May transiently vanish after plasma exchange 4
If negative but MOGAD suspected: retest during acute attacks, treatment-free intervals, or 1-3 months after plasma exchange/IVIG 6

Red flags requiring confirmatory testing 1, 6
Use a second (or third) methodologically different cell-based assay if results are discrepant 6
IVIG pretreatment may cause false-negative or false-positive results 1
Progressive disease course is very atypical for MOGAD and should prompt reconsideration 4
Documentation requirements: All results should document immunoglobulin class detected, assay type, antigenic substrate, biomaterial used, titer/concentration, assay-specific cut-offs, and performing laboratory 1, 6, 2