Detection of beta-2 transferrin is considered pa of standard evaluation when CSF leak is suspected. Nasal and ear fluids are tested for detection of the beta-2 transferrin band by immunofixation electrophoresis (IFE) or Western blot analysis as a diagnostic tool for the presence of CSF or perilymph. This test is helpful in the differential diagnosis for CSF otorrhoea or CSF rhinorrhoea. The beta-2 transferrin band has not been detected in multiple fluids including serum, ear fluid, nasal secretions, saliva, tears or endolymph, indicating the specificity of the slower beta-2 transferrin isoform for CSF.