[Sensitivity and efficiency of intrathecal IgG secretion in multiple sclerosis. Comparison of several indices and formulas using pre-established values of specificity].

: To furnish greater specificity in the analysis of cerebrospinal fluid from patients suspected of having multiple sclerosis, we studied the sensitivity and efficiency of indices and formulas used to calculate intrathecal IgG synthesis in a group of 49 patients with clinically defined multiple sclerosis, using cutoff values based on preestablished levels of specificity (75 and 90%), and compared the findings to those for a control group of patients with other neurological diseases. The best results were obtained with the indices and formulas based on computer models of brain-blood barrier function set forth most recently, namely Reiber's formula and Ohman's index, which had the highest specificity with the least loss of sensitivity.