Measurement of IgG and albumin content of cerebrospinal fluid, and its interpretation.

A high correlation (r 0.85) normally exists between the concentration of albumin and of lgG in cerebrospinal fluid (CSF). The correlation is still better (r = 0.96) if the concentrations of the two proteins are also measured in plasma and the CSF/ plasma ratios compared for albumin and lgG. The scatter diagram for these ratios in persons without disease of the nervous system is most useful as a reference when differentiating between local lgG production in the subarachnoid space and an increase in CSF protein for other reasons. The analysis can be performed on less than 0.1 ml of CSF, in contrast to agarose-gel electrophoresis, for which 5-10 ml is necessary.