Table 2

Poser criteria for the diagnosis of clinically definite multiple sclerosis (MS) and laboratory supported MS (modified from Poser et al⁶)

	Clinical relapse	Clinical evidence (number of lesions)	Paraclinical lesions	CSF OCBs
Clinically definite MS		2^2-150	2^2-151
Clinically definite MS		2^2-150	1 and	1 or more

Laboratory supported definite MS		2^2-150	1 or	1 or more	+
		1	2^2-152		+
		1	1^2-152 and	1^2-152 or more	+

Clinical evidence means documented neurological signs relating to a lesion. Paraclinical lesions are lesions found by investigation that are distinct from clinical lesions.
↵2-150 Two clinical relapses involve lesions at different times and different sites.
↵2-151 Can substitute documented clinical signs of one episode with strong typical historical information.
↵2-152 Evidence of two different lesions separated in time (that is, not both present initially). CSF, cerebrospinal fluid; OCBs, oligoclonal bands, NA, not available.