The quantitation and fractionation of proteins in cerebrospinal fluid

The quantitation of CSF proteins has important clinical applications. Often the total protein level is quite useful but does not provide sufficient information to differentiate the disease state of the patient. The IgG/albumin index is a parameter frequently used as an indication of IgG production within the central nervous system. Hence, the levels of the albumin and globulin fractions must often be determined. Many methods exist for quantitations of total protein in CSF and the levels of the major protein fractions and for separating the various proteins present into their major protein fractions. For total protein quantitation, the turbidimetric method is common, but the Coomassie brilliant blue method may be the method of the future. For separation and quantitation of protein fractions, electrophoresis or some immunologic method is frequently used. The more sophisticated isoelectric focusing and two-dimensional techniques are limited to use mostly by research laboratories. With further sophistication of techniques for separating proteins and interpretation of the results thereby obtained, the methods which are now limited to research may be adapted by routine laboratories in the future.