Real-world applicability of the 2024 McDonald criteria for multiple sclerosis diagnosis in Portugal.

BACKGROUND

The revised McDonald criteria (2024) introduced new imaging and laboratory biomarkers, allowing earlier and more accurate diagnosis of Multiple Sclerosis (MS).

OBJECTIVES

To assess the applicability of the new criteria in Portugal and identify diagnostic tool availability and implementation barriers.

METHODS

We conducted a national survey of neurologists from public hospitals involved in MS diagnosis and follow-up. Descriptive statistics and Pearson's chi-square tests identified factors associated with systematic implementation.

RESULTS

24 of 30 centres responded (80.0%). MRI protocols are routinely implemented in 58.3% of centres, with active Neuroradiology collaboration in 41.7%. CVS and PRLs were not routinely analyzed in 37.5%. OCBs are mostly performed locally (58.3%), while κFLC index is routinely measured in 41.7%. VEPs were timely in 75.0%, while OCT had inadequate response times in 54.2%. Systematic application was reported by 70.8% and associated with higher patient volume (p=0.035), Neuroradiology collaboration (p=0.022), and shorter CSF biomarkers turnaround times (OCB/κFLC index, p=0.003). Main barriers were limited technical resources (78.9%) and time constraints (42.1%).

CONCLUSION

Access to advanced biomarkers remains heterogeneous. Systematic implementation is associated with higher volume centres, Neuroradiology collaboration, and faster access to CSF biomarkers, highlighting priorities for equitable and timely adoption of the revised criteria.