Multiple sclerosis: incorporation of results of laboratory techniques in the diagnosis.

In a retrospective study of 100 multiple sclerosis patients we compared the diagnostic classification according to the Schumacher/Rose criteria and the newest criteria, proposed by Poser et al. It is clear that by incorporating the results of laboratory investigations in the diagnostic criteria a firm diagnosis of multiple sclerosis can be reached more often and at an earlier stage of the disease. Evaluating abnormal laboratory findings, we found that it was possible to detect more than 90% of diagnostically important findings, i.e. findings effecting a change in diagnostic classification (from possible multiple sclerosis to probable or definite, from probable to definite), using only two of the laboratory tests: cerebrospinal fluid analysis and visual evoked response. Because the results of laboratory tests contributing to diagnostic classification are not specific for multiple sclerosis, the importance of evaluating the complete differential diagnosis of diseases that can be confused with multiple sclerosis is stressed.