The diagnosis of CSF fistulae on the basis of detection of beta 2-transferrin by polyacrylamide gel electrophoresis and immunoblotting.

A sensitive method is described for the detection of beta 2-transferrin, a transferrin-variant found only in cerebrospinal fluid (CSF). The determination of beta 2-transferrin, whose presence is characteristic of CSF-admixtures in secretions, is performed in three steps. The proteins of the secretion are separated by polyacrylamide gel electrophoresis and then transferred electrophoretically onto a nitrocellulose sheet. Finally, the transferrins on the nitrocellulose sheet are specifically detected by an antibody reaction. The bands are visualized either by using antibodies conjugated with peroxidase or by protein A gold. With the exception of certain cases (Ritchie, R. F. & Smith, R. (1976) Clin. Chem. 22, 497-499; Görg, A. et al. (1983) Human Genetics 64, 222-226) beta 2-transferrin is found only in cerebrospinal fluid, and not in other body fluids. Therefore the detection of beta 2-transferrin can be used for the diagnosis of rhino- and otoliquorrhea. The advantage of this method is that beta 2-transferrin can be unequivocally identified by the use of a relatively small amount of technical equipment. CSF can therefore be clearly identified in secretions. An additional advantage of the method is its high sensitivity.