The relation between the results of 7 biological markers (cells, total protein, 
albumin, IgG, IgG ratio, Tibbling ratio, and Tourtellotte's formula) and 4 
paraclinical tests (PEV, PEATC, CT and MR) in 236 patients with multiple 
sclerosis (MS) not selected by the localization of symptoms were studied. One 
hundred forty-one had clinically defined MS, 22 had defined MS supported by a 
laboratory and 68 had clinically probable MS. The existence of a relation 
between PEV and MRI abnormality and the increase in the concentration and the 
ratios of intrathecal IgG synthesis and the degree of certainty of disease 
diagnosis was demonstrated. The most sensitive test was MRI (93%) followed by 
VEP (83%) and BAEP (60%) and the sensitivity of the study with high resolution 
CT including 59 patients explored by double enhancement and delayed cut off was 
very low (33%). It was considered that for the lack of a specific diagnostic 
test the use of biological markers PEV and MR constituted a necessary aid in the 
diagnosis of MS.