The upgraded McDonald criteria for multiple sclerosis (MS) has presented increased diagnoses in patients with clinically isolated syndrome (CIS), however a recent study of the criteria suggests that they may misguide to a number of false positive MS diagnoses in patients with a milder disease condition.

“In our data, specificity of the 2017 criteria was significantly lower than for the 2010 criteria,” Roos M. van der Vuurst de Vries, MD, from the department of neurology at Erasmus Medical Center in Rotterdam, the Netherlands, and her colleagues wrote in JAMA Neurology. “Earlier data showed that the previous McDonald criteria lead to a higher number of MS diagnoses in patients who will not have a second attack.”

Dr. van der Vuurst de Vries and her team analyzed data from 229 patients with a CIS who did an MRI of the spinal cord to check for dissemination in space (DIS); out of these, 180 patients were graded for both DIS and dissemination in time (DIT) and had a “baseline MRI scan that included T1 images after gadolinium administration or scans that did not show any T2 hyperintense lesions.” A baseline lumbar puncture was performed on some patients if clinically required.

The 2010 and 2017 McDonald criteria for MS was used to assess patients, and results were calculated using sensitivity, specificity, positive predictive and negative predictive values, and accuracy at 1-year, 3-year, and 5-year durations. “The most important addition is that the new criteria allow MS diagnosis when the MRI scan meets criteria for DIS and unique oligoclonal bands (OCB) are present in [cerebrospinal fluid], even in absence of DIT on the MRI scan,” the researchers wrote. “The other major difference is that not only asymptomatic but also symptomatic lesions can be used to demonstrate DIS and DIT on MRI. Furthermore, cortical lesions can be used to demonstrate dissemination in space.”