A comparison between agar gel electrophoresis and CSF serum quotients of IgG and albumin in neurological disease.

CSF and serum was obtained from 216 patients with neurological or psychoneurotic symptoms and the concentrations of albumin and IgG were immunologically determined. The IgG/albumin index, calculated as the quotient of the CSF/serum ratios of IgG and albumin was compared with electrophoresis on agar gel. In "normal" cases, the IgG/albumin index was between 0.26-0.66. Pathological electrophoresis, i.e. with two or more IgG bands in the gamma globulin region was found in 85 per cent of the MS patients; in 29 per cent of the patients with a possible demyelinating disease; in 41 per cent of patients with CNS infection; and in 4 per cent of patients with other neurological disorders; whereas an increased IgG/albumin index ( greater than 0.66) was found in 88 per cent of the MS patients; in 43 per cent of the patients with a possible demyelinating disease; in 50 per cent of the patients with CNS infection; in 11 per cent of patients with immunological disorders; and in 18 per cent of patients with other neurological diseases. The increase of the IgG/albumin index was sometimes moderate (0.67-0.90), except in patients with MS, syphilis and other CNS infections, where a pathological electrophoresis combined with an IgG/albumin index above 1.0 was found to be a valuable support for the clinical diagnosis.