Updated McDonald Criteria Validated for MS Diagnosis in Real-World Settings

The 2024 McDonald criteria demonstrate high sensitivity and accuracy, but moderate specificity, in the diagnosis of multiple sclerosis (MS), according to study results presented at the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) Congress 2025, held in Barcelona, Spain from September 24 to 26, 2025.

While the 2024 McDonald criteria has been recommended for the diagnosis of MS, the validation of these criteria in real-world settings is lacking. To address this gap, researchers studied the application and diagnostic performance of the 2024 criteria in patients with suspected MS.

Patients with clinical or radiologic features suggestive of MS underwent brain and spinal cord magnetic resonance imaging (MRI), along with additional tests as needed, such as lumbar puncture, orbital MRI, and optical coherence tomography. The 2017 McDonald criteria were prospectively applied during follow-up, and patients were classified as having MS, possible MS, or radiologically isolated syndrome (RIS). The 2024 McDonald criteria were then retrospectively applied to the same diagnostic workup, using the 2017 criteria as a reference standard.

A total of 192 patients were evaluated for suspected MS, of whom the mean age was 42.3 years, 64% were women, and the mean follow-up was 271 days. Among these patients, 25% (n=48) were diagnosed with conditions other than MS, like functional neurologic disorder or migraine.

Application of the 2024 McDonald criteria, compared with the 2017 version, resulted in more patients being diagnosed with MS based on MRI and other testing (121 vs 97), while the number of patients classified as having possible MS (14 vs 24) and RIS (9 vs 23) decreased (P <.05 for all).

The 2024 criteria demonstrated high sensitivity (98.1%; 95% CI, 93.2%-99.8%) and diagnostic accuracy (86.1%; 95% CI, 79.4%-91.3%), though specificity was moderate (55.5%; 95% CI, 38.5%-70.7%).

The researchers concluded, “The new criteria have high sensitivity, but reduced specificity reflecting increased MS diagnosis in patients not meeting the 2017 McDonald criteria.”

Disclosures: Multiple authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.